- Mix 1/2 cup of warm water and 1 tablespoon of borax in a cup until dissolved
- Mix 2 tablespoons of glue, 1 tablespoon of cornstarch, and food colouring (optional) in separate cup
- Pour the glue mixture into the cup with water and borax; squish mixture with hands until it's no longer sticky
- Once mixture hardens, remove from cup and roll the mixture in your hands firmly to form a ball until hardened
Note: If your ball still feels sticky give it a little dunk in the borax water and it should firm up.