I began noticing a multitude of extremely stubborn black and/or green spots on some of my solid antique silver pieces displayed in the open, and the only thing I could correlate it to was some minor drywall work in my home some months ago, which of course produced a layer of drywall dust on everything that I've been fighting ever since. I panicked and looked on the web and found the following article about Chinese drywall imported 2006/2007 which exudes sulfuric fumes that tarnish silver uniformly, evidently: Link This article specifically mentions antique silver, though I have checked the label on the sheetrock used in my home, and it says "Made in USA," and it was purchased in 2008, so I doubt it falls under the category of this contaminated drywall, but I just had to wonder if there's some kind of a desiccant in ordinary, USA drywall akin to salt that might be making these terrible black spots. Does that make sense? They polish out eventually, but they leave a whitish halo on the silver surface even when polished away. I searched the 925 site and found a thread on silver sickness, but the Chinese drywall article wasn't referenced. Has anyone experienced this problem with non-Chinese drywall dust? I'm thinking of tarnish bagging everything that isn't in a tight cabinet to try to arrest the damage process.