I have built up a fair number of sheds that i've found while i've been out over the years, and wanted to start doing some carvings in them. my question is, some of them like a few of the moose and caribou antlers have a greenish mold on them and some other discoloration? can that be cleaned off with out grinding on it. and once i get them clean can i restain them, and if so with what will regular wood stain work?