I've got an old folding knife and the sheath that came with it. The knife has brass fittings on each end and whenever I take it out (which isn't very often), the brass is discolored from the leather. This doesn't really bother me as I can polish it. The issue is, if it's left in for a long period of time, green gunk is stuck to the brass and sometimes the wood. It's thick enough that I have to scrub it off with a cloth.
I don't know leatherworking vernacular but, I would describe the inside of the sheath as a raw, unfinshed surface and I'm looking to find out what I might be able to treat it with to keep that gunk from forming and sticking to the knife. Might there be some way to rub and smooth out the leather to get rid of that raw surface.
Thanks