OK, I know I should find a picture for best effect (or be able to post it):
Just bought a two coin Br. Honduras lot for USD13.20. In it was a 1954 50c that was usual crappy. The prize was a 1960 25c which is quite scarce to rare in higher (unc.) grades - it was really ugly with what could have been early verd.
HOWEVER, the thing that struck me in pictures was that the rims were sharp (no, not a proof) and representative of what could be a nice unc. specimen. Not to mention a bunch of muck in the devices and lettering.
Long story short, I cleaned it with ammonia - NO friction, just tamping with cotton buds - and then rinsed it well. Voila! I had what is likely an MS63 or 64 coin. As I had bought the Richard Stuart MS63 example for USD120 or so, this was quite a find. Really more about the difficulty of finding such more than the money.
Perhaps I can email a reader and they can post pictures?? Sold Ebay item: 303634274564