Play-Doh is made from starch, specifically two types of starches called amylose and amylopectin. When both starches are added together, the mixture will gelatinize. To prevent the dough from drying out, a retrogradation inhibitor like a waxy starch is added. Surfactants are also included to make the compound less sticky and allow it to be molded. Play-Doh must be stored in air tight containers to prevent the retrogradation inhibitors from drying out and causing the compound to dry out over time.