A couple of questions/requests for advice:
I've had my Yamaha 642 for about four years, and a few months ago (much to my dismay) the silver began to literally come off of the horn along the 3rd valve slide and outer tube where I hold it with my left hand. I found this odd for a couple of reasons: a) the silver is fine other places I touch my horn a lot (like the bar my right hand touches behind the valves and b) I've never had problems with plating before; I don't think my body chemistry is very acidic.
First of all, could this be a manufacturer's defect? I have always been "good" to my euph, I give it a bath it every few months, keep everything in good working order, etc. Is this a common problem or a rare occurrence?
Also, is there anything I can do to keep this from continuing and protect my horn? Usually after playing I now get a greenish discoloration on my left hand from being exposed to the raw brass, and every now and then I see another piece of silver flake off. Is there some kind of covering that will keep this from spreading and protect my hands?