What's up with that?

I have absolutely no idea why a child thinks eating crayons is a good idea. I have scolded her each time she does it and still she keeps on eating. The other kids try to keep them away from her but when you're busy coloring you don't really notice the sly little hand that reaches up over the edge of the table to grab that stray crayon near the edge. Then one of two things can happen: the other children finally notice their baby sister with crayon crumbs on her face or I find the baby with crayon crumbs on her face. Either way I have to get her to spit them out, rinse off her hands and face and mouth and pick up the mess she may have made on the floor where she started chewing. It's really strange to me and I hope she grows out of this phase quickly because we are running out of crayons that are big enough for the kids to hold on to.