Vinegar is not just for cooking!! It is an excellent product for cleaning and medicinal purposes and just about anything you can possibly imagine. I bet you have it in your cupboard, so mix some up with a warm water solution and give it a try. Take a look at this site for helpful tips on the many things vinegar can be used for.
I'm not sure if this will work, but a Magic Eraser is truly magic in my opinion. It cleans things nothing else will touch. You could try it and no harm done if it doesn't. That's also the beauty of vinegar, it doesn't damage like harsh chemicals.
Marcia from MarciAnnDesigns says
" . . . a Magic Eraser . . . cleans things nothing else will touch."
Reckon how one of these magic erasers will work on those fine little lines around my eyes? The vinegar didn't do so well on the wrinkles.
Silicone is one of the toughest things out there, just try and remove it from your bathtub to re caulk it if you don't believe me LOL Hot Hot water will take care of the crayon wax and then whatever works for the remaining crayon dye.