How we researched this guide
We compared 4 slime activators and checked slime-making guides and recipe sources before writing. Contact solution works in slime because it contains boric acid and sodium borate. The alternatives below work for the same reason or by a different route, and each one is described honestly with its drawbacks.
We did not test any product hands-on. Maker claims are written as rated or stated by the maker, and owner experience is paraphrased from the linked sources.
The 30-second answer
The best contact solution alternative for slime is borax powder dissolved in warm water: one teaspoon in one cup of warm water makes the classic activator, and it gives the thickest, least sticky slime. Liquid starch is the easiest ready-to-use alternative, Elmer’s slime activator is the pre-mixed option, and cornstarch mixed with water is the only truly borax-free route, though it makes a different kind of slime.
Quick picks
Best results
Borax powder in warm water
Best if you want the classic result. One teaspoon of borax in one cup of warm water gives the thickest slime with the least stickiness.
Easiest
Liquid laundry starch
Best if you want no mixing. Pour it straight into the glue a little at a time until the slime forms, and knead until smooth.
Ready-made
Elmer’s slime activator
Best if you want a pre-mixed bottle. It blends the borax and liquid-starch approaches and works with any glue.
Truly borax-free
Cornstarch and water
Best if you must avoid borax entirely. Mix cornstarch into glue or water until it thickens. It is a different texture from classic slime.
Quick compare
| Activator | Mixing | Texture | Borax-free | Best for |
|---|---|---|---|---|
| Borax water | 1 tsp per cup | Thick, least sticky | No | Classic slime |
| Liquid starch | None | Stretchy, classic | No | Easy slime |
| Elmer’s activator | None | Smooth, reliable | No | Beginners |
| Cornstarch | Mix to thicken | Thick, paste-like | Yes | Borax allergies |
Why contact solution works in slime
Slime forms when borate ions link the glue’s polymer chains together, turning liquid glue into a stretchy solid. Contact solution works as an activator only when it contains boric acid and sodium borate, so check the label: not every saline solution will work. Baking soda is usually added first as a buffer, about a quarter teaspoon per bottle of glue, and then the solution is added a few drops at a time. Every alternative in this guide either supplies the same borate ions or thickens the glue by another route.
How to choose an alternative
Borax content matters
Borax powder, liquid starch, and Elmer’s activator all contain borate compounds under different names, such as boric acid or sodium borate. If someone is sensitive or allergic to borax, none of these is a safe substitute, even though the label says something different. Only cornstarch slime is truly borax-free.
Texture you want
Borax water gives the thickest slime with the least mess. Liquid starch gives a stretchy, classic slime texture. Elmer’s activator sits between the two. Cornstarch gives a thick paste that behaves differently from glue slime and will not stretch the same way.
Clear slime is harder
Clear slime is tricky because activators like contact solution and liquid starch can cloud it and make it less transparent. Borax powder is the better choice for clear slime, and clear laundry detergent is sometimes used for the same reason. Expect some clouding whatever you use.
Supervise children
Borax can irritate skin and eyes and is harmful if swallowed, so children should not handle borax powder on their own. Adults should mix the activator, and everyone should wash hands after playing. Keep slime away from mouths, and throw away slime that smells odd or grows mould.
Borax powder: the classic alternative
Borax powder is the original slime activator and still the most reliable. Dissolve one teaspoon of borax powder in one cup of warm water and stir until it clears, then add it to the glue a little at a time, kneading as you go. It makes the thickest slime and cuts stickiness and mess better than the other options. The drawback is handling: it is a powder that irritates skin and eyes, so an adult should mix it, and it must be kept away from young children.
Liquid laundry starch: the easy alternative
Liquid starch, sold for laundry, is a ready-to-use activator that needs no mixing. Add it gradually to the glue until the slime forms, then knead it until it is smooth and stretchy. It is cheap, easy to find in the laundry aisle, and gives a consistent classic slime texture. It can be messy and may need more kneading than borax slime, and like contact solution it contains borate compounds, so it is not a borax-free option.
Elmer’s slime activator: the pre-mixed alternative
Elmer’s slime activator is a bottled liquid that blends the borax and liquid-starch approaches, and it works with any glue. Use it exactly like contact solution in a slime recipe: add a little at a time and knead until the texture is right. It is the most convenient option for beginners and for classrooms, because there is no powder to measure and no mixing step. It still contains borate compounds, so it is not suitable for anyone avoiding borax.
Cornstarch: the truly borax-free alternative
Cornstarch slime is made by mixing enough cornstarch into glue or water to absorb the liquid and form a thick texture. It contains no borax, no boric acid, and no sodium borate, so it is the only option here for people who are sensitive or allergic to borax. Be honest about the trade-off: it does not behave like classic glue slime. It is thicker, less stretchy, and closer to a paste, and it dries out faster. For young children and borax-free play, that trade is worth making.
Troubleshooting
| Problem | Likely cause | Fix |
|---|---|---|
| Slime will not form | Solution lacks borate | Check label for boric acid |
| Slime too sticky | Not enough activator | Add activator a little at a time |
| Slime too stiff | Too much activator | Knead in a little warm water |
| Slime cloudy | Activator clouds glue | Use borax water for clear slime |
| Slime smells or moulds | Old or dirty slime | Throw it away, make fresh |
Who should NOT use borax activators
Anyone sensitive or allergic to borax: borax powder, liquid starch, contact solution, and Elmer’s activator all rely on borate compounds. If borax is the problem, only cornstarch slime is a real alternative.
Very young children without supervision: slime ingredients can irritate skin and eyes and are harmful if swallowed. An adult should mix activators and supervise play.
Final verdict
Use borax water for the best classic slime, liquid starch for the easiest slime, Elmer’s activator for the most convenient slime, and cornstarch when borax must be avoided entirely. Always check the label: the activator only works if it contains borate, whatever its name.
Frequently Asked Questions
What can I use instead of contact solution for slime?
Borax powder dissolved in warm water, liquid laundry starch, Elmer’s slime activator, or cornstarch. Borax water gives the best classic result, and cornstarch is the only truly borax-free option.
Why does contact solution work in slime?
Contact solution contains boric acid and sodium borate. The borate ions link the glue’s polymer chains together, turning liquid glue into stretchy slime.
Does any saline solution work for slime?
No. Only solutions that list boric acid and sodium borate as ingredients will activate slime. Plain saline will not work, so check the label first.
How much borax do I need for slime?
One teaspoon of borax powder dissolved in one cup of warm water is the standard activator. Add it to the glue a little at a time and knead until the slime forms.
Is liquid starch better than borax for slime?
Liquid starch is easier because it needs no mixing, and it gives a stretchy classic texture. Borax water gives a thicker, less sticky slime. Both contain borate compounds.
How do I make slime without borax?
Mix cornstarch into glue or water until it thickens. This is the only truly borax-free method here, but the result is thicker and less stretchy than classic glue slime.
Why is my slime too sticky?
It needs more activator. Add activator a few drops at a time and knead well between additions. Adding too much at once makes the slime stiff, so go slowly.
Is slime safe for children?
Slime is safe for supervised play with hand washing afterwards. Borax can irritate skin and eyes and is harmful if swallowed, so adults should mix activators and young children should be supervised.
Sources & changelog
Manufacturer and maker sources:
- How to make slime without baking soda, ShiftyChevre
- How to make activator for slime, KidsToyHome
- How to make clear slime without contact solution, Steamsational
- How to make slime without borax, HowToSlime
Changelog — November 5, 2026: guide first published. No affiliate links are included. Slime activators are household products; brand names are given only where the source names them.
By Leo, Founder, WinchInsider
Leo writes WinchInsider guides from maker specifications, manuals, and owner reports, so readers can choose workshop tools with facts instead of guesses.