That Rio Wax Brite solution–the stuff that smells like oranges–If
I’m right, the same stuff that you can buy in the store for much
less. It is called De-Solv-It. It will dissolve gum, oil, oil-based
paints, and since matt wax is a petroleum product, DSI will also
dissolve the upper layers of wax models. With the foam things to
provide some abrasion, it should work well.