I'd never heard of these till now. Are these like abrasive belts but without the abrasive on them and you can load the surface with compound ? I was thinking of turning an old 400grit belt inside out and use the bare side with compound, but there's the joint in the way.
I have recently tried using my old green Scotchbrite belts that have gone flat, loaded them up with black oxide compound (supposed to be 220grit). It comes out looking something like 400-600grit.It isn't polishing , but it helps give a nice satin field-grade finish and makes doing a nice hand (maybe not even need 320grit) followed by this belt before doing a hand rubbed finish. But it wastes a lot of compound 'cos most of it gets flung around the grinder as you're trying to load the belt.
The cloth belts sound interesting. Jason.