Pumpkin+Bear: Beeswax Manipulatives

I've been trying to pay more attention to my Pumpkin+Bear etsy shop this autumn (or is it winter now? It's 19 degrees outside, and there's snow on the ground. That's probably winter, right? But I'm still in denial, so I'm going to say it's autumn still), since my goal is to buy Matt's and the children's Christmas presents solely from my earnings, so I finally made myself get around to squatting out in the snow with my camera to prep something that the kids and I have had around forever: these beeswax alphabet and number manipulatives:

If you like to work with beeswax and you've got children the right ages for moveable alphabets and numbers, these would actually be a great choice to DIY--they're non-toxic, waterproof, absolutely perfect for tactile and sensory learning, and although they're breakable, you can simply recast the broken ones.

And when you're done with moveable alphabets and numbers (we finally are--can you believe it? Where did my little preschoolers GO?!?), you can recast the whole lot into something new rather than having to throw anything away. 

I use these silicone alphabet and number molds, and I love them. I've used them to mold in beeswax, crayon, and plaster of Paris so far. Any other ideas for a molding material? I'll do it!