I play on a 1960 Buescher Aristocrat Mark III Bari Sax, and with it's age the finish on it has started to corrode a bit (I personally like how it looks however), thus revealing what seems to be copper. I played on it a lot, and just so happened to forget to empty my spit valve or do any cleaning at all before leaving it for a month while I recovered from having my wisdom teeth pulled. I started playing again for about a month, failing to remember the sacred ritual of cleaning my sax. When I finally emptied the spit valve, all of it was green, and the cloth I use to clean the inside was green as well. Is this just from the copper, or is there mold in my sax? Do saxes even have copper in them, or is it just the metal corroding on it? Thanks!