Electric griddle or hot plate
Crayons, peeled
Aluminum foil
White paper
Sponge

Heat griddle to 380 degrees until hot. Then turn down to 275 degrees to keep warm. Be sure the griddle has aluminum foil over it. Have lots of peeled crayons ready. Let the children draw with crayons onto the foil. It should melt easily; if it doesn't, raise the heat a bit. Hold down foil with sponge. Give each child a piece of paper. Press the white paper onto the foil. Lift the paper off the foil and see the print. Put new foil on and get ready for the next child. Lots of supervision needed.