Before you start, make some spaghetti sauce. Well, that's what I did because I needed some cans. You may already have some cans set aside for recycling. Make sure they are clean and dry. Place as many will fit into a saucepan and fill the pan with a few inches of water, enough that your cans won't bob around.
Sort your crayons according to tones. For example, I combined yellow and dandelion, purple and indigo, blue and cerulean, red and scarlet, etc. Have the kids peel the wrappers off. You can help them out by using an exacto knife to slice it open first, but be very careful. I have a scar on my left hand from a box cutter incident many years ago.
If you don't have enough cans for each separate color, start with the lighter colors first or a primary color and then a secondary color that is made with it. Melt yellow, then orange or pink, then red.
Let the kids break up the crayons and put each color/tone in its own can. Heat on low and once they begin to melt, stir with a craft stick (one for each color) until liquified.
Carefully, pour into silicone ice cube trays or candy molds. This is a job for an adult because the hot wax pours quickly and may splatter. Let sit until solid or place in freezer to speed up the process. You'll probably have to help pop the crayons out of the silicone molds, but the ones in candy molds should fall right out when you flip it over. I recommend doing it over a towel to soften their landing. No matter which type of mold you use, you won't be able to use it for anything else after making crayons.
I bought a two-pack of silicone heart ice cube trays in the dollar spot at Target with intentions of giving them as Valentine's gifts. Wouldn't these be cute bagged up with a tag that says "You color my world, Valentine"?
The silicone molds left more of a matte finish. Personally, we like the super smooth feel of the candy mold crayons. We were only slightly tempted to eat one because they reminded us of cute little chocolates.