Bookbinders use folders made of bone; they're called "bone folders." Available at art supply stores and online. They look an awful lot like bone scales. There are also new razors with bone scales. Don't know why they're kicking up trouble on ebay, unless people are in fact sneaking other stuff through under the label.
I'm recycling some old ivory scales into wedges, but not on anything I'll sell. As said above, it's a shame to waste it.