Common types include air-dry clay that hardens without baking, oven-bake polymer clay that stays soft until baked, and soft reusable modeling compounds used in playsets and refill packs.
Most modeling-compound playsets and clay kits are labeled for children around 3 years and up; many kits list 4 years and up, while polymer clay sampler packs are often labeled 8 years and up.
For dried modeling compound, allow it to fully dry and then remove residue by scraping or vacuuming. Many products and reviews also describe some clays as easy to mold and simple to clean; for reusable compounds, wipe tools and store the clay in sealed containers to prevent drying.
Some larger playsets list battery requirements and note adult assembly. For example, one product specifies 2 AA batteries (required, not included) and that adult assembly is required.