We made crayons today using my handy toaster oven, some silicon molds and broken crayons. I had to peel the paper off the crayons ahead of time myself, and got the molds from my friendly neighborhood Swedish home supply store [they have flowers, fish and stars]
it took some jiggering to get the stars out of the mold without the stars breaking, and the crayons had to go through the melting process a few times - 200 F degrees for 7 minutes seemed to do the trick for getting the crayon to melt all the way.
We had the kids pick out the colors they wanted and filled the trays. The toaster oven was in another room with a fan running and the windows open - when melting the wax smells a bit like a hot glue gun. I also discovered that it was best not to mix materials - soy and paraffin waxes don't seem to like each other. The kids, however, were ecstatic with the end results.