photo via e-sling.net
1. Mix borax and 1/2 cup of water.
2. In another bowl, mix glue and 1/4 cup of water. Add food coloring.
3. Pour the glue solution into the bag. Then, add 3 tbsp of the borax solution, do not mix.
4. Add the polystyrene beads.
5. Seal bag and knead by hand until mixed. Let the bag stand for 15 minutes. Then knead for a few more minutes.