I just got this the other day, and it was a rusty, muddy mess! I decided to do a little cleaning today and got some results. I started with navy jelly, then graduated to oxalic acid. The acid seemed to work better. That eastern European mud was a nightmare to get out/off! A hammer and screwdriver got a lot, but not all off. Wire brushes even came up against a formidable cake of rust and mud. I guess that 60+ years in the ground will do that to most things.