A friend of mine asked me this question today and I had to admit I have no clue to the reason.
..........He bought a used pretty cheap no name Jazz about a year and a half ago, it came with a nice black canvas padded gig bag from the seller. After a few months he noticed the chrome on the bass tarnishing, nothing too serious but losing it's shine all tne same.
Anyway about 4 months ago, he traded the no name in for a Squier CV jazz, he kept the gig bag, so the Squier has lived in it since new. Now he's noticed the chrome on the CV is starting to tarnish aswell, again nothing serious but tarnishing. The gig bag is clean inside and out, immaculate condition, doesn't smell or anything, just an ordinary gig bag, I would have no problem using it.
My mate asked me if I thought it was just a coincidence or could the gig bag be possibly causing the tarnishing? anybody have any idea?
cheers.