Nora and I spent one whole afternoon a few days back melting old crayons and pouring out the colors onto small canvases. We also used the foil to create molds of things we had around the house and pouring melted crayon wax in them to create interesting shapes.
Nora adding a piece of rolled foil onto hers (above). See her heart mold (top one). In mine, the canvas below, I kept using pealed pieces of wax we've poured onto foil and trying to attach them to my canvas. We used various home tools to make scratches on our wet/soft wax.