This document provides instructions for making plastic at home from milk and vinegar. The process involves heating milk with a small amount of food coloring, then adding vinegar which causes the casein protein in the milk to separate out into a solid plastic-like material. This material is collected on a paper filter as the liquid drains away. After drying for a day or two, the result is a homemade plastic ball or sheet that can be molded from the casein plastic produced from common household ingredients.