Most modeling-compound playsets are labeled for children aged 3 years and up. Oven-bake polymer clay items commonly list a recommended age of 8 years and up.
Oven-bake polymer clay remains soft until it is cured in a home oven. Instructions specify baking at 275 °F (130 °C) for 15 minutes per 1/4 inch (6 mm) of thickness. Product notes warn not to microwave the clay and not to exceed the recommended temperature or time.
Store oven-bake polymer clay in a cool, dry place out of direct sunlight and below about 77 °F (25 °C). When stored properly it typically has an expected shelf life of a few years; refrigeration or freezing may extend that life.
Most clay and modeling-compound items list no battery requirements. At least one larger playset specifies it requires 2 AA batteries (not included).