Our Bible school theme was based on Heifer Project, a program that provides animals, plants and water to countries in need who invite the program into their country. Part of the program is that after the animal reproduces, the first offspring is passed on to someone else. We developed four days of lessons on "God's Gift of..People, Animals, Land (Plants) and Generosity".
After baking and cooling time, we painted each round with acrylic paint and wiped it off immediately with squeezed out wet paper towels, leaving some paint in the indentations left by the nature findings. Give each student pre-moistened paper towels and have a few larger wet rags in the middle of the table for them to wipe their hands on. This reduces mess and cuts down on bathroom trips to wash hands. Be aware: acrylic paint can be washed out of clothes when it is wet, but it will set when it dries.