Vince,

I have absolutely no idea. It sounds like an interesting idea. The slurry has garnets in it, which in theory would act as an abrasive. The leather might make for a slower cutting action and smoother finish than you'd get off the coticule...

You should be able to easily clean that off the leather if it doesn't work. As long as the leather doesn't get too wet, there's no harm in trying. Let us know how it works out!

Josh