Posted: Mon Dec 18, 2006 5:16 pm
I'll take a wild guess and say it depends on what the corrosive influence is. Brown to black signifies sulfides and oxides; red would seem to imply an acidic environment (leaching out zinc and leaving copper).
A horn pulled out of the acid bath after cleaning looks reddish, for example.
A horn pulled out of the acid bath after cleaning looks reddish, for example.