I grated up some old crayons ahead of time for this activity, trying to separate colors in a muffin tin, but of course they would end up getting mixed together anyway. I wrapped pieces of cardboard with tin foil and set everything out on her picnic table.
At first Kay carefully sprinkled pinches of the chalk gratings onto the paper but such diligence was bound to be short-lived. Eventually she just dumped the whole muffin tin onto her foil.
We tried setting them out in the sun, but apparently we picked a day when the sun wasn't quite hot enough. After several hours there was no sign of melting happening, so we brought them in the house and put them in the oven. 5 minutes at 200 degrees was more than enough to melt it. It was fun seeing all the colors melt into each other. Kay's dump-it-all-on technique turned out to be the best way to do it, because she ended up with a colorful work of art.
I like how the Happy Hooligans and Mercies Raining Down painted the foil first. I think that would have made for an even more impressive result!