Tips
How to Store Slime and How Long It Lasts
How long slime lasts depending on the recipe, how to keep it soft, how to revive it when it dries out, and the signs that moldy slime belongs in the trash.
A great slime can last for weeks… or dry out overnight, or get covered in tiny spots within a few days. It all depends on the recipe and on how you store it. Here’s how long each type of slime lasts, how to keep it in good shape, and when it’s time to toss it.
How long does slime last?
| Type of slime or dough | Usual lifespan in a closed container |
|---|---|
| Glue slime (easy, clear, glitter, crunchy) | Several weeks |
| Fluffy slime | A few days of “fluffy,” then it deflates |
| Butter slime | Dries out faster: keep an eye on it |
| Cornstarch and water | One day at most |
| Marshmallow, gelatin | Same day only |
| Chia, fiber | A few days in the fridge |
| Cooked playdough | Up to two months in the fridge |
These times are rough guides: heat, dirty hands or a lid that doesn’t close properly cut them short.
5 rules to keep slime in shape
- An airtight container: this is rule number one. Left out in the air, the water in slime evaporates; it forms a crust, then hardens. A jar with a screw-on lid or a zip-top bag sealed tight does the job.
- Clean hands before playing: dirt and crumbs bring in bacteria and mold.
- At room temperature, out of the sun: away from the heater, sunny windowsills and a hot car in summer. Heat makes it soft and runny.
- No freezer, no microwave: extreme cold and heat damage its structure. The fridge is only useful for food-based doughs (chia, fiber) and playdough.
- One container per slime: mixing several slimes in one jar ends up as a single gray blob.
How to revive a tired slime
- It dried out a little: a few drops of warm water and a long knead. A small dab of hand lotion helps too.
- It got hard: soak it in warm water for one minute, then knead.
- It’s too soft and runny: a few drops of contact lens solution, added by an adult, then knead.
- Your fluffy slime deflated: that’s normal; you can still play with it as classic slime.
For every symptom, the Slime Fixer gives you detailed steps.
When should you throw slime away?
There’s no saving a slime that:
- smells bad (sour or musty);
- has spots that are black, green or fuzzy white: that’s mold;
- is dusty or full of hair even after cleaning;
- has been in a little one’s mouth.
Throw it in the trash (never down the sink or the toilet: it can clog the pipes), wash the container in hot, soapy water and make a new one. It’s the perfect excuse to try a new texture from our slime texture glossary.
Label everything
A simple trick for collections: write the slime’s name and the date you made it on a piece of masking tape, and stick it on the lid. That way, you always know which ones are the oldest. The Slimer’s Logbook keeps track of your successes too.
What about store-bought slime?
Follow the directions on the package. A store-bought slime that changes smell, oozes or gets unusually sticky shouldn’t be used anymore. If you have doubts about a product, the U.S. Consumer Product Safety Commission (CPSC) posts recalls and product safety warnings on its website, where you can search them (in France, the official RappelConso site does the same job). Our parents’ guide pulls all the precautions together.