Pour 1/2 cup of white school glue into a bowl
Add 1/2 cup of water and mix well
Add food coloring if desired and stir
Add 1/4 teaspoon of baking soda and mix
Add 1 to 2 tablespoons of contact lens solution slowly while stirring
Keep mixing until the slime starts to form
Knead the slime with your hands until it is no longer sticky
Add a little more contact lens solution if needed
Store the slime in an airtight container