My friend plays on a Vincent Bach 3c and i just now noticed the bowl of his piece is now a brownish gold. It started just like any other silver mouthpiece. It's like his saliva is tarnishing the piece. It's still smooth inside and it still plays like a dream for him. Now this is the really weird part. I traded him a megatone for a 5c he had. AND NOW IT'S GOLD INSIDE TOO!!!! When I got it it was still silver. Wierd. What's up with this? Is it bad, what should I do?