We used this for our preschool classes. It's safe and inexpensive...and cleans up well.
List of Ingredients
1 C salt
2 C flour
2 t cream of tartar
2 C water
2 T oil
Food coloring (optional)
Recipe
Mix dry ingredients. Add food coloring to water if desired. Add wet ingredients, stir and cook 3-5 minutes over medium heat until congealed. The dough will be a little sticky. Knead in remaining liquid. Store in airtight container.