How we researched this guide
We compared six degreasers across three families — alkaline concentrates, citrus concentrates and a ready-to-use spray — checking each against maker and listing documents: Oil Eater via its listing data and Grainger record, Zep via its product pages and safety data sheet, Purple Power via its directions and maker FAQ, Chemical Guys via its maker how-to material, and Spray Nine via its description and retailer spec blocks. Dilutions print only where a maker documents them.
For surface rules we checked each maker’s own cautions and reviewed owner reports and retailer records, linked in each review. We do not test degreasers and we print no prices. Degreasing sits alongside fluid work in our heavy-duty oils and fluids archive and the sibling truck oil drain pan guide.
The 30-second answer
Match the chemistry to the soil and the surface, then dilute exactly as the maker directs. Most shops should buy Oil Eater Original: one concentrate with documented mixes for parts washers, floors and general degreasing. For the heaviest hydraulic and floor grease, Zep Industrial Purple is the strongest mix here. Purple Power serves farm steel and concrete, Zep Heavy-Duty Citrus and Chemical Guys Orange cover citrus work and engine bays, and Spray Nine Grez-Off is the ready-to-use option. Our maintenance checklist covers the rest of the service routine.
Best Overall
Oil Eater Original Cleaner Degreaser, 1 Gallon
Best if one bottle must cover the whole shop: a water-based concentrate with maker dilutions for parts washers, pressure washers and floors, listed for aluminium and painted surfaces.
Strongest Concentrate
Zep Industrial Purple Degreaser Concentrate, 1 Gallon
Best if baked-on hydraulic oil defeats milder cleaners: one gallon makes up to 25 gallons of working solution at a documented heavy mix. It is also the harshest product here, so the safety box matters.
Best for Hydraulic Oil and Farm Use
Purple Power Industrial Strength Degreaser, 1 Gallon
Best if farm and fleet grease is the job and the surfaces are steel and concrete: a concentrated alkaline with a maker-documented 1:1 parts-washer mix. Its maker bans it on aluminium and stainless, and this guide honours that ban.
Best Citrus Concentrate
Zep Heavy-Duty Citrus Degreaser, 1 Gallon
Best if you want citrus solvency on engines, tools and concrete in one concentrate that makes up to 16 gallons. Keep it off auto paint, glass, acrylic, plastics, leather and natural stone, exactly as the maker directs.
Best for Engine Bays
Chemical Guys Signature Series Orange Degreaser, 1 Gallon
Best if the work is diesel engine bays near paint and plastics: a citrus concentrate with three documented strength bands and a maker routine built around cool engines.
Best Ready-to-Use
Spray Nine Grez-Off Heavy Duty Degreaser, 32 oz
Best if mixing is the friction: a ready-to-use, water-based spray documented for fifth wheel grease, hydraulic fluid and moly grease on engines and farm equipment, with no dilution step.
Quick compare: the six degreasers at a glance
| Product | Form | Size | Documented working dilutions | Check Price |
|---|---|---|---|---|
| Oil Eater Original | Alkaline concentrate | 1 gal | 10:1 general; 3–4:1 parts sink | Check Price |
| Zep Industrial Purple | Alkaline concentrate | 1 gal | 20 fl oz per gal heavy; 5 fl oz per gal light | Check Price |
| Purple Power 4320P | Alkaline concentrate | 1 gal | 1:1 parts and power washer (maker FAQ) | Check Price |
| Zep Heavy-Duty Citrus | Citrus concentrate | 1 gal | Heavy dilution or full strength; makes up to 16 gal | Check Price |
| Chemical Guys Orange | Citrus concentrate | 1 gal | 6:1 extreme; 10–15:1 medium; 25–40:1 light | Check Price |
| Spray Nine Grez-Off | Ready-to-use spray | 32 oz | None — use as supplied | Check Price |
Dilution is water to product unless a maker states ounces per gallon. Stronger is not better: it is how aluminium gets hazed.
Degreaser finder: match the product and dilution to the job
Pick the job and how heavy the soil is. Every result names a degreaser from this guide, the maker-documented dilution for that job, and its button. Ratios are water to product unless ounces per gallon are stated.
How to choose a heavy equipment degreaser
Soil first: grease, hydraulic oil, or road film
Name the soil before you name a brand. Baked engine grease answers to citrus strength and dwell; fresh hydraulic oil answers to a strong alkaline at its documented heavy mix; floor oil needs dwell plus a stiff brush in the concrete pores. The finder maps each soil to a documented mix.
Dilution discipline
A concentrate is a set of different cleaners at different ratios, and the maker’s chart is the product. Oil Eater alone documents mixes from 3 to 1 in a parts sink to 40 to 1 in an agitating unit. Mixing by feel wastes concentrate and leaves slippery floors.
Surfaces: aluminium, stainless, paint and plastics
This is where guides stay vague and owners pay for it. Purple Power’s maker bans it on aluminium and stainless outright. Zep Citrus is banned by its maker on auto paint, glass, acrylic and plastics. High-pH concentrates demand a spot test and a prompt rinse. Aluminium-heavy machines start with Oil Eater or citrus.
Application: spray, pressure washer, or parts washer
Decide the delivery method before buying the size. Ready-to-use spray suits spot work and fifth wheel grease. Pressure washers want a concentrate whose maker documents machine use — Oil Eater and Purple Power both do. Parts washing is its own discipline with its own ratios, covered in the dilution table below.
Safety data and PPE
Read the hazard line before the marketing line. Zep Industrial Purple carries a maker safety data sheet classifying it for severe skin burns and eye damage, which settles the glove and eye-protection question for every strong alkaline here. Ventilation, cool surfaces and no mixing with other chemicals are baseline rules, not fine print.
Runoff and the wash pad
Biodegradable describes the cleaner, not the oily water it lifts off a machine. That runoff carries the oil you just removed. Work on a contained pad, lay absorbent pads first, keep rinse water out of storm drains, and handle collected waste under local rules.
Degreaser dilutions by job
| Job | Product | Maker-documented dilution | Source |
|---|---|---|---|
| General cleaning and floors | Oil Eater Original | 10 parts water to 1 part product | Maker guidance via trade record |
| Sink-style parts washing | Oil Eater Original | 3–4 parts water to 1 part product | Maker guidance via trade record |
| Ultrasonic parts washing | Oil Eater Original | 20–25 parts water to 1 part product | Maker guidance via trade record |
| Parts washer, steel parts | Purple Power 4320P | 1:1 with water; strengthen if needed | Maker FAQ |
| Heavy grease and oil | Zep Industrial Purple | 20 fl oz per gallon of water | Maker product page |
| Light cleaning | Zep Industrial Purple | 5 fl oz per gallon of water | Maker product page |
| Extreme engine cleaning | Chemical Guys Orange | 6 parts water to 1 part product | Maker how-to via listings |
| Light maintenance cleaning | Chemical Guys Orange | 25–40 parts water to 1 part product | Maker how-to via listings |
| Concrete oil stains | Zep Heavy-Duty Citrus | Full strength or heavy dilution; 5 min dwell; brush | Maker listing directions |
| Spot degreasing | Spray Nine Grez-Off | Ready to use; no dilution | Maker product description |
Keep this table with the chemicals: a labelled bottle with the ratio written on it prevents the two classic errors — too weak to work, or strong enough to mark aluminium. The same discipline runs through our heavy-duty truck winch guide and diesel truck winch guide.
Heavy equipment degreasers by budget
| Tier | What you get | Example pick from this guide |
|---|---|---|
| Ready-to-use tier | No mixing, no chart, spray and rinse | Spray Nine Grez-Off |
| Single-gallon concentrate tier | One alkaline for floors, parts and general work | Oil Eater Original / Purple Power 4320P |
| Citrus concentrate tier | Citrus solvency for engines, tools and concrete | Zep Heavy-Duty Citrus / Chemical Guys Orange |
| Shop-strength tier | Highest documented yield and strongest heavy mix | Zep Industrial Purple |
Every tier demands the same PPE and runoff care. Spend more and you buy yield and strength, not permission to skip the safety box.
Types of degreasers compared
| Type | Pros | Cons | Best for |
|---|---|---|---|
| Alkaline concentrate | Strongest on mineral and hydraulic oil; huge yield | Surface bans and PPE are real; never let it dry | Shops and farms (Zep Industrial Purple, Purple Power, Oil Eater) |
| Citrus concentrate | Strong on grease and tar-like soils; pleasanter to work around | Maker bans on paint and plastics vary | Engine bays and mixed shops (Zep Citrus, Chemical Guys Orange) |
| Ready-to-use spray | Zero mixing error; instant spot work | No yield advantage on whole-machine washes | Spot grease and small fleets (Spray Nine Grez-Off) |
| Parts-washer fluid use | Long soak does the work; solution reused for days | Needs the documented ratio; steel-only for strong alkalines | Rebuild benches (Oil Eater sink mix, Purple Power 1:1) |
Detailed reviews of the best heavy equipment degreasers
Each review follows the same order — why it earns its award, specs, fit, pros and watch-outs, owners, skips, and pairings.
Best Overall: Oil Eater Original Cleaner Degreaser, 1 Gallon
Best Overall
Why the Oil Eater Original Cleaner Degreaser, 1 Gallon is our pick
Oil Eater earns the top slot on documented range: the maker publishes a dilution for nearly every delivery method a shop owns, from a 3 to 1 parts sink to a 40 to 1 agitating unit, and the formula is listed for aluminium and painted surfaces where the strong alkalines here are banned.
Oil Eater Original Cleaner Degreaser, 1 Gallon key specs
- Part number: AOD1G35437 (Kafko International)
- Size: 1 gallon concentrate
- Base: water-based alkaline
- General dilution: 10 parts water to 1 part product
- Parts sink dilution: 3–4 parts water to 1 part product
- Ultrasonic dilution: 20–25 parts water to 1 part product
- Machine use: parts washers, pressure washers, scrubbers
- Surfaces listed: aluminium, metals, painted surfaces, plastic, rubber
- Properties: biodegradable, non-corrosive, non-flammable, low VOC
- Approvals: USDA categories A1, A4, A8
- Working note: cool surface only; minimum 55 F
Oil Eater Original Cleaner Degreaser, 1 Gallon: fits and best for
Best for mixed fleets that wash parts as often as machines, and for aluminium-heavy equipment where Purple Power is banned by its maker. It is the finder’s default for floors and parts. More context: our oils and fluids archive.
Oil Eater Original Cleaner Degreaser, 1 Gallon pros and watch-outs
Pros
- Widest documented dilution range here
- Listed for aluminium and painted surfaces
- Works in parts and pressure washers
- Biodegradable, non-flammable, water-based per maker
Watch-outs
- Ratio discipline is on you — five mixes to track
- Cool-surface rule rules out hot-engine shortcuts
- Too-rich mixes leave a slippery rinse
Oil Eater Original Cleaner Degreaser, 1 Gallon: what owners report
Trade coverage describes long-running fleet use on trucks and heavy equipment, with the wash line stated as safe on polished aluminium, rubber, vinyl and paint when used as directed — see the Recycling Product News fleet wash report.
The industrial record agrees: the Grainger parts-washer listing files it as a water-based parts washer cleaner for metals and plastics, and Cutting Tool Engineering notes its use on machinery, engines and tools.
Oil Eater Original Cleaner Degreaser, 1 Gallon: who should not buy
Skip it if you will not measure ratios at all — a concentrate used by feel underperforms a ready-to-use spray. The Spray Nine Grez-Off removes the mixing step entirely.
Oil Eater Original Cleaner Degreaser, 1 Gallon: pair it with
Pair it with the Zep Professional Sprayer from Safety essentials, ratio written on the bottle.
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Tip: mix the parts sink at 3 to 1 for rebuilds and 4 to 1 for routine service, written on the washer lid. While parts soak, work through our maintenance checklist.
Strongest Concentrate: Zep Industrial Purple Degreaser Concentrate, 1 Gallon
Strongest Concentrate
Why the Zep Industrial Purple Degreaser Concentrate, 1 Gallon is our pick
When hydraulic oil has baked onto a loader frame, this is the mix the other products escalate to. The maker documents heavy and light dilutions, a 3 to 5 minute dwell, and a yield of up to 25 gallons from one gallon — and its safety data sheet is equally clear that this strength demands real PPE.
Zep Industrial Purple Degreaser Concentrate, 1 Gallon key specs
- Part number: R45810 (Zep)
- Size: 1 gallon concentrate
- Yield: up to 25 gallons ready to use (maker)
- Heavy dilution: 20 fl oz per gallon of water
- Light dilution: 5 fl oz per gallon of water
- Dwell: 3–5 minutes; do not let it dry (maker)
- Surfaces per maker: unfinished concrete, metal, fiberglass, masonry, asphalt
- SDS class: Skin Corrosion 1, Eye Damage 1, Danger
- Form: purple liquid concentrate
- Application: spray, mop or machine
Zep Industrial Purple Degreaser Concentrate, 1 Gallon: fits and best for
Best for steel-framed machines, unfinished concrete and the worst hydraulic soils in a shop that already works gloved and goggled. Keep it off delicate paint and bare aluminium unless diluted, spot-tested and rinsed at once. See our truck winch guide.
Zep Industrial Purple Degreaser Concentrate, 1 Gallon pros and watch-outs
Pros
- Strongest documented heavy mix in this guide
- Up to 25 gallons of working solution per gallon
- Low-foaming, easy-rinse positioning for industrial use
- Exact ounce-per-gallon dilutions published
Watch-outs
- SDS hazard class demands gloves and eye protection, always
- High-pH: spot-test and rinse discipline mandatory
- Never let it dry on the surface, per the maker
Zep Industrial Purple Degreaser Concentrate, 1 Gallon: what owners report
An independent review at GlennSaid reaches the same working rules this guide prints: patch-test first, dilute for delicate surfaces, wear gloves, ventilate, and manage runoff responsibly.
Retailer records agree on size and yield — see the True Value spec block for R45810 — and the maker’s own safety data sheet is the document behind the PPE rules here.
Zep Industrial Purple Degreaser Concentrate, 1 Gallon: who should not buy
Skip it if your equipment is aluminium- or paint-sensitive and the crew will not spot-test — the cost of one careless full-strength pass is a marked finish. The Oil Eater Original is the forgiving strong cleaner in this guide.
Zep Industrial Purple Degreaser Concentrate, 1 Gallon: pair it with
Pair it with the TitanFlex 8-mil gloves from Safety essentials: the product those gloves exist for.
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Tip: work in sections small enough to rinse inside the dwell window; a dried ring of alkaline is a second job. See our essential accessories guide.
Best for Hydraulic Oil and Farm Use: Purple Power Industrial Strength Degreaser, 1 Gallon
Best for Hydraulic Oil and Farm Use
Why the Purple Power Industrial Strength Degreaser, 1 Gallon is our pick
Purple Power is the farm-shop alkaline: concentrated, phosphate-free, and documented by its maker for parts washers and power washers at a simple 1:1 starting mix. It earns its place with an equally simple limit from its own maker: never on aluminium or stainless steel. This guide builds its routing around that limit.
Purple Power Industrial Strength Degreaser, 1 Gallon key specs
- Part number: 4320P (Purple Power)
- Size: 1 gallon (128 fl oz) concentrate
- Parts washer dilution: 1:1 with water (maker FAQ)
- Power washer dilution: 1:1 with water (maker FAQ)
- Base: water-based; no solvents or silicones (maker FAQ)
- Properties: biodegradable, non-abrasive, non-flammable, phosphate-free
- Label: gloves, eye and skin protection, ventilation, spot test
- Banned by maker: aluminium and stainless steel
- Also banned: car exteriors, glass, painted surfaces, wheel rims
- VOC status: compliant in all states (maker FAQ)
Purple Power Industrial Strength Degreaser, 1 Gallon: fits and best for
Best for steel implements, tractor frames, concrete pads and farm parts washers, where its 1:1 machine mixes are easy to teach and repeat. Aluminium wheels, tanks and brightwork route to Oil Eater or citrus instead. See our tractor winch guide.
Purple Power Industrial Strength Degreaser, 1 Gallon pros and watch-outs
Pros
- Documented 1:1 mixes for parts and power washers
- Concentrated farm alkaline at gallon scale
- Phosphate-free and non-flammable per the listing
- Maker FAQ answers machine-use questions directly
Watch-outs
- Maker bans it on aluminium and stainless — no exceptions printed here
- Never let it dry on the surface, per the label
- Not for car washing or painted finishes, per the maker
Purple Power Industrial Strength Degreaser, 1 Gallon: what owners report
Review roundups repeat the pattern owners describe: fast on engines, tools and shop grease, with gloves and a surface test treated as part of the job — see the Purple Power review roundup.
The maker Purple Power FAQ is the more important owner document: it is where the 1:1 machine mixes and the aluminium and stainless ban are stated, and this guide follows it over any forum shortcut.
Purple Power Industrial Strength Degreaser, 1 Gallon: who should not buy
Skip it if your fleet is aluminium-heavy — wheels, tanks, or polished boxes — because the maker ban covers exactly your work. The Oil Eater Original is listed for aluminium and painted surfaces.
Purple Power Industrial Strength Degreaser, 1 Gallon: pair it with
Pair it with the PIG oil-only pads from Safety essentials: a 1:1 machine mix moves a lot of oil, and pads keep it out of the drain.
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Tip: dedicate one labelled jug to the 1:1 mix so nobody strengthens it by feel. See our pickup winch guide.
Best Citrus Concentrate: Zep Heavy-Duty Citrus Degreaser, 1 Gallon
Best Citrus Concentrate
Why the Zep Heavy-Duty Citrus Degreaser, 1 Gallon is our pick
Zep’s citrus concentrate is the middle path between detergent alkalines and solvent sprays: a d-limonene formula listed for engines, tools, concrete, aluminium and stainless steel, making up to 16 gallons. Its maker ban list is different, not shorter — no auto paint, glass, acrylic, plastics, leather or natural stone.
Zep Heavy-Duty Citrus Degreaser, 1 Gallon key specs
- Part number: ZUCIT128 (Zep)
- Size: 1 gallon concentrate
- Yield: makes up to 16 gallons (spec sheet)
- Active character: natural citrus solvent, d-limonene
- pH range: 11–12 (product description)
- Use on: engines, tools, concrete, fiberglass, aluminium, stainless
- Do not use on: glass, acrylic glass, plastics, auto paint, leather, natural stone
- Concrete method: full strength or heavy mix, 5 min dwell, brush, rinse
- Form: liquid concentrate
Zep Heavy-Duty Citrus Degreaser, 1 Gallon: fits and best for
Best for mixed shops that degrease engines one hour and a concrete pad the next, and want citrus solvency without solvent fumes. Painted bodywork routes to the Chemical Guys pick at its light band. See our F-150 winch guide.
Zep Heavy-Duty Citrus Degreaser, 1 Gallon pros and watch-outs
Pros
- Citrus solvency for engines, tools and concrete
- Listed for aluminium and stainless steel
- Up to 16 gallons of working solution per gallon
- Documented dwell-and-brush concrete method
Watch-outs
- Maker bans it on auto paint, glass, acrylic and plastics
- Older concrete stains may need a second application, per the maker
- Owner coverage thinner than for Oil Eater
Zep Heavy-Duty Citrus Degreaser, 1 Gallon: what owners report
Owner coverage for this concentrate is thinner than for the alkaline picks, and we say so plainly: the practical record sits mostly in retailer listings rather than long-form owner write-ups.
That record — ZUCIT128 spec sheet and the listing data — agrees on the points printed here: the 16-gallon yield, the surface and ban lists, and the brush-into-the-pores concrete method.
Zep Heavy-Duty Citrus Degreaser, 1 Gallon: who should not buy
Skip it if most of your work is painted panels or plastic-heavy cabs — the maker ban list covers your daily surfaces. The Chemical Guys Orange Degreaser at its light band is the paint-adjacent citrus here.
Zep Heavy-Duty Citrus Degreaser, 1 Gallon: pair it with
Pair it with the Zep Professional Sprayer from Safety essentials: one labelled bottle for the heavy mix.
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Tip: on unsealed concrete, flood the stain, wait the full dwell, and brush before rinsing. See our how-to guides.
Best for Engine Bays: Chemical Guys Signature Series Orange Degreaser, 1 Gallon
Best for Engine Bays
Why the Chemical Guys Signature Series Orange Degreaser, 1 Gallon is our pick
Engine bays punish the wrong degreaser twice: grease that survives, and finishes that do not. This citrus concentrate answers with three maker-documented strength bands and a routine written for bays — cool engine, electrics covered, gentle pre-rinse, short dwell, low-pressure rinse.
Chemical Guys Signature Series Orange Degreaser, 1 Gallon key specs
- Part number: CLD_201; gallon model CLD_201SW
- Size: 1 gallon (128 fl oz) concentrate
- Extreme dilution: 6 parts water to 1 part product
- Medium dilution: 10–15 parts water to 1 part product
- Light dilution: 25–40 parts water to 1 part product
- Soils named by maker: motor oil, coolant, hydraulic fluid, diesel fuel
- Use on: engines, machinery, tools, wheels, undercarriages, floors
- Method: cool engine; cover intake, alternator, battery; low-pressure rinse
- Spot-test first per maker guidance
- Form: citrus-based liquid concentrate
Chemical Guys Signature Series Orange Degreaser, 1 Gallon: fits and best for
Best for diesel bays and undercarriages where paint, hoses and plastics sit inches from the grease, and for owners who will use the three strength bands instead of one mix for everything. See our winch power guide before bay work near terminals.
Chemical Guys Signature Series Orange Degreaser, 1 Gallon pros and watch-outs
Pros
- Three documented strength bands
- Maker routine written for engine bays
- Citrus formula aimed at oil, coolant and diesel soils
- Gallon size suits repeated fleet bay work
Watch-outs
- Bands demand measuring, not guessing
- Detailing-skewed owner record; fewer fleet reports
- Short dwell: heavy bays need brush work
Chemical Guys Signature Series Orange Degreaser, 1 Gallon: what owners report
A roundup on Corvette Forum describes keeping a gallon on hand and pairing it with elbow grease on stubborn buildup — the maker’s spray, brush, rinse discipline.
Retailer listings for the line, such as the Black Ops Auto Works listing, cross-check the CLD_201 part family and the concentrate positioning behind the specs printed above.
Chemical Guys Signature Series Orange Degreaser, 1 Gallon: who should not buy
Skip it if your soils are mostly baked hydraulic oil on steel frames — a bay-focused citrus is the wrong escalation path. The Zep Industrial Purple at its heavy mix is built for that soil.
Chemical Guys Signature Series Orange Degreaser, 1 Gallon: pair it with
Pair it with the Zep Professional Sprayer from Safety essentials, mixed at the medium band and labelled.
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Tip: cover alternator and intake before the pre-rinse, not after the spray. See our winch battery guide.
Best Ready-to-Use: Spray Nine Grez-Off Heavy Duty Degreaser, 32 oz
Best Ready-to-Use
Why the Spray Nine Grez-Off Heavy Duty Degreaser, 32 oz is our pick
Grez-Off exists for jobs that never justify mixing a gallon: a fifth wheel plate, a hydraulic weep across a frame rail, a trailer sidewall pressure washing leaves filmed. The maker documents it for exactly those soils — fifth wheel grease, hydraulic fluid, heavy moly grease — in a water-based spray.
Spray Nine Grez-Off Heavy Duty Degreaser, 32 oz key specs
- Part number: 22732 (Spray Nine)
- Size: 32 fl oz trigger spray
- Form: ready to use; no dilution
- Base: water-based, biodegradable per maker
- Soils named: grease, fifth wheel grease, oil, hydraulic fluid, moly grease, tar
- Use on: engines, machinery, tools, benches, floors, trailers, farm equipment
- Surfaces named: stainless, chrome, concrete, asphalt, vinyl, rubber, plastic, metal
- Properties per maker: nonflammable, no fumes, no abrasives, no acids
- Compliance: USDA approved; VOC compliant, all 50 states
Spray Nine Grez-Off Heavy Duty Degreaser, 32 oz: fits and best for
Best for spot degreasing, small fleets, and any crew whose mixing discipline you do not want to audit. Whole-machine washes belong to the concentrates above on yield alone. See our portable winch guide.
Spray Nine Grez-Off Heavy Duty Degreaser, 32 oz pros and watch-outs
Pros
- No mixing, no ratio errors
- Documented for fifth wheel and moly grease
- Water-based and biodegradable per the maker
- No fumes or abrasives per the maker description
Watch-outs
- 32 oz runs out fast on big work
- No concentrate yield for big wash days
- Soak-and-scrub still required on baked soils
Spray Nine Grez-Off Heavy Duty Degreaser, 32 oz: what owners report
A truck owner review on the retailer page praises Grez-Off on engine bays and trailer sidewalls, where pressure washing alone left the film behind — see the retailer product page for 22732.
The single-bottle record at Desertcart UK confirms the 22732 model and size behind the specs above.
Spray Nine Grez-Off Heavy Duty Degreaser, 32 oz: who should not buy
Skip it if you wash whole machines weekly — you will empty bottles doing a concentrate’s job. The Oil Eater Original at its general mix is the economical whole-machine answer.
Spray Nine Grez-Off Heavy Duty Degreaser, 32 oz: pair it with
Pair it with the PIG oil-only pads from Safety essentials: spraying over a pad keeps grease out of the drain.
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Tip: spray, wait, and wipe a test patch before a whole sidewall. See our winch cover guide.
Spec comparison: all six degreasers side by side
| Spec | Oil Eater Original | Zep Industrial Purple | Purple Power 4320P | Zep Citrus | Chemical Guys Orange | Spray Nine Grez-Off |
|---|---|---|---|---|---|---|
| Form | Concentrate | Concentrate | Concentrate | Concentrate | Concentrate | Ready to use |
| Size | 1 gal | 1 gal | 1 gal | 1 gal | 1 gal | 32 oz |
| Part number | AOD1G35437 | R45810 | 4320P | ZUCIT128 | CLD_201 | 22732 |
| Documented dilutions | 10:1 general; 3–4:1 sink; 20–40:1 machines | 20 oz/gal heavy; 5 oz/gal light | 1:1 parts and power washer | Heavy or full strength; to 16 gal | 6:1 extreme; 10–15:1 medium; 25–40:1 light | None |
| Parts washer use | Yes, documented | Not published | Yes, 1:1 (maker FAQ) | Not published | Not published | No — spray format |
| Pressure washer use | Yes (maker) | Not published | Yes, 1:1 (maker FAQ) | Not published | Not published | No — spray format |
| Aluminium | Listed for use | Spot-test, dilute, rinse at once | Banned by maker | Listed for use | Spot-test per maker | Metal listed; spot-test |
| Paint | Listed (painted surfaces) | Keep off delicate paint | Banned by listing | Auto paint banned by maker | Bay routine built for painted areas | Not published |
| Biodegradable | Yes (maker) | Not published | Yes (listing) | Citrus solvent formula | Not published | Yes (maker) |
| Hazard headline | Cool surface; spot test | SDS: skin and eye corrosion, Danger | Gloves and eye protection (label) | pH 11–12 | Spot-test first | No fumes, no acids (maker) |
| Check Price | Check Price | Check Price | Check Price | Check Price | Check Price | Check Price |
Read the table by your constraint: aluminium, machine use, or hazard headline.
How to degrease heavy equipment safely
Start cold and contained. Let engine and hydraulics cool fully — makers direct application to cool surfaces — then lay pads, cover intakes, alternators and battery terminals, and knock off loose dirt with a gentle pre-rinse. Mix the documented ratio for the job, label the bottle, and spot-test a hidden patch on aluminium, stainless or paint before committing.
Work in sections small enough to rinse inside the dwell window, brush where soil is baked, and rinse top down. Never let a strong alkaline dry on the work, and keep rinse water on the pad, out of storm drains. The routine pairs with our maintenance checklist, winch installation guide and drain pan guide.
Disposal follows used-oil logic: the US EPA used-oil guidance tells changers to collect oily waste in leak-proof containers and keep it out of drains and ground. Oily pads and runoff go out under local rules — check them before the first wash.
Safety essentials
Safety rules
- Gloves and eye protection are mandatory with every concentrate here. Zep Industrial Purple carries a maker safety data sheet for severe skin burns and eye damage.
- Never degrease a hot engine or hydraulic system. Makers direct application to cool surfaces; heat speeds reactions and turns rinse water to steam.
- Never let a strong alkaline dry on aluminium, stainless or paint. Dwell is minutes, then rinse — a dried pass hazes finishes.
- Spot-test first on aluminium, stainless, painted and plastic surfaces, and obey each maker’s ban list even when another product allows the surface.
- Contain runoff: pads down first, keep oily rinse water out of storm drains, dispose of waste under local rules.
- Never mix degreasers with other chemicals, ventilate, and wash skin after contact. Keep chemicals from children and animals.
Three accessories complete the setup, each with a verified listing. The Zep Professional Sprayer Bottle, 32 oz, 3-pack (HDPRO1) is the chemical-resistant adjustable sprayer this guide’s ratios assume — one labelled bottle per mix.
TitanFlex Heavy Duty Orange Nitrile Gloves, 8-mil are the hand protection the safety box requires; confirm your size on the listing before ordering.
PIG Oil-Only Absorbent Mat Pads (MAT454) absorb oil without taking up water — the containment layer under every wash in this guide. Our accessories guide covers the recovery side of the kit.
Troubleshooting degreasing problems
| Symptom | Likely cause | Fix |
|---|---|---|
| Grease survives the first pass | Mix too weak for the soil, or dwell cut short | Step to the maker’s next documented band and brush during dwell; never free-pour stronger |
| White streaks or haze on aluminium | A banned or undiluted alkaline sat too long | Rinse at once; metal polish may restore the finish per the maker FAQ; reroute aluminium work to Oil Eater or citrus |
| Floor still slippery after rinsing | Mix was too rich, per the Oil Eater maker note | Rinse again and weaken the next mix; slippery means more water, not more product |
| Paint looks dulled after washing | A product crossed its maker ban list, or dried on the panel | Stop, rinse, and switch to the bay-routine pick at its light band; spot-test before any retry |
| Parts washer solution dies early | Ratio drifted as solution was topped up by feel | Recharge at the documented ratio (Oil Eater 3–4:1; Purple Power 1:1) and skim oil between jobs |
| Runoff heading for a drain | No containment laid before spraying | Stop, dam the flow with pads, collect the liquid, reset the area |
Who should NOT buy these degreasers
Owners who will not measure a ratio. Five of these six picks are concentrates whose results live in their dilution charts. If mixing will always be by feel, buy the ready-to-use Grez-Off and accept its bottle limits. The same honesty applies to sizing in our winch sizing guide.
Aluminium-polish fleets shopping on strength alone. The two strongest alkalines here carry the strictest aluminium rules, up to an outright maker ban. If your machines are alloy tanks, wheels and boxes, start at Oil Eater or citrus, as the finder routes you.
Anyone washing where runoff cannot be contained. Gravel yards and open drains turn degreasing into oil relocation. If no containment is possible, the responsible purchase is a wash facility visit, not a stronger chemical. Our how-to guides take the same line.
Shops chasing a disinfectant or a solvent parts bath. Nothing here disinfects, and nothing here is a petroleum solvent bath. Those are different products with different rules, deliberately left out of this guide.
Final verdict
Best Overall — Oil Eater Original Cleaner Degreaser, 1 Gallon: Check its price.
Strongest Concentrate — Zep Industrial Purple Degreaser Concentrate, 1 Gallon: Check its price.
Best for Hydraulic Oil and Farm Use — Purple Power Industrial Strength Degreaser, 1 Gallon: Check its price.
Best Citrus Concentrate — Zep Heavy-Duty Citrus Degreaser, 1 Gallon: Check its price.
Best for Engine Bays — Chemical Guys Signature Series Orange Degreaser, 1 Gallon: Check its price.
Best Ready-to-Use — Spray Nine Grez-Off Heavy Duty Degreaser, 32 oz: Check its price.
FAQ
What is the best degreaser for heavy equipment?
For most shops and fleets, Oil Eater Original: one water-based concentrate with maker dilutions for parts washers, pressure washers and floors, listed for aluminium and painted surfaces. For the heaviest baked hydraulic oil on steel, Zep Industrial Purple is stronger.
Can I use Purple Power on aluminium?
No. The maker FAQ bans Purple Power on aluminium and stainless steel, warning it can leave white streaks or a hazy film, restorable in some cases with a metal polish. Route aluminium work to Oil Eater or a citrus pick in this guide.
What dilution should I use in a parts washer?
Use the maker ratio for your product: Oil Eater documents 3 to 4 parts water to 1 part product for sink-style parts washing, and Purple Power’s maker FAQ specifies 1:1 with water for parts washers, strengthened only if the soil demands it.
Is it safe to degrease a hot engine?
No, not at all. Makers direct application to cool surfaces, and the bay routine here starts with a fully cooled engine, covered intake, alternator and battery, and a low-pressure rinse. Heat speeds reactions and turns a routine wash into a burn risk.
Can degreaser runoff go down the drain?
No. Biodegradable describes the cleaner itself, not the oil it lifts off the machine. Work on a contained pad with absorbent pads down first, keep rinse water out of storm drains, and dispose of collected oily waste under your local rules.
Why did my degreaser leave white streaks?
A strong alkaline sat too long, dried on the surface, or was used on a surface its maker bans — the classic case is a purple alkaline on aluminium. Rinse immediately, shorten the dwell, dilute to the documented band, and spot-test before the next pass.
Citrus or alkaline degreaser: which is better for engine bays?
Citrus, at a documented band, for most bays: it suits the mix of grease, hoses, plastics and painted panels found there, and the Chemical Guys pick publishes three strength bands for that work. Reserve the strongest alkalines for steel and concrete.
Do I really need gloves and eye protection?
Yes. Zep Industrial Purple’s maker safety data sheet classifies it for severe skin burns and eye damage, and Purple Power’s label directs gloves and eye and skin protection. Treat the strongest product’s rules as the shop standard for every concentrate.
How long should degreaser dwell before rinsing?
Follow the maker window for your product: Zep Industrial Purple specifies 3 to 5 minutes, Zep Citrus about 5 minutes on unsealed concrete stains, and the bay routine uses a short dwell with brush work. The shared rule is stricter than any number: never let it dry.
Can I pressure wash with these degreasers?
Only where the maker documents machine use. Oil Eater lists pressure washers among its applications, and Purple Power’s maker FAQ gives a 1:1 power-washer mix. For products whose makers do not publish a machine dilution, apply by sprayer and rinse at low pressure instead.
Sources & changelog
Manufacturer and listing sources: Oil Eater record — Grainger, Oil Eater dilutions — Material Handling Wholesaler, Zep Industrial Purple — Zep, Zep Industrial Purple SDS, Purple Power FAQ — maker, Zep Citrus spec sheet, Engine degreaser guidance — Chemical Guys, US EPA used-oil guidance.
Owner sources (paraphrased in the reviews): Zep Purple long-form review, Purple Power review roundup, Corvette Forum owner roundup, Grez-Off owner reviews — retailer page, Oil Eater fleet wash report. Dilutions and cautions are as the makers state them; our affiliate disclosure explains how links in this guide work.
Changelog — October 17, 2026: guide first published.
By Leo, Founder, WinchInsider
Leo researches truck and shop gear from maker documents and owner reports. More about WinchInsider.
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