So, I researched online for some solutions and decided to try melting them. Here's a picture of their crayons before.
The only small sized silicone mould I have is this mini donut maker. It seemed to be the right size for the crayons.
I put the crayons in the oven left my kitchen. When I returned after a very short while, my kitchen was very smokey. The crayons melted very quickly and were smoking!! I thought there was a fire in my oven but there wasn't.
I took them out immediately and placed them in the fridge.
Here's a picture of them removed from the mould.
As you can see from the picture, the crayons have separated. The bottom yellowish portion draws clear while the top coloured portion works like a normal crayola.
Overall, I'm disappointed with the results. Perhaps I left the crayons in my oven too long or the heat setting on my oven was too high. Oh well... What's done's done.
My advise if you want to attempt this, once you've put the crayons in your oven, watch your oven like a hawk. :)