Ingredients: Acetone (at least enough to fill a coffee cup half way) styrofoam (the more you have, the more it will make) 1 coffee cup Fill the coffee mug with about a quarter inch of acetone. Place the styrofoam in the acetone. It should fizzle. Keep adding more styrofoam until you reach a good sized blob. You can pick it up and play with it. Stretchofoam can be washed if you do not wish to get acetone on your hands because it may dry your hands out, but by washing it loses some of it's stretchy properties.