It gives the feeling that this glass has been around for a long while. Forgotten, which is probably what the whole town of Bodie is...forgotten and isolated. In fact, beautiful job in the entire gallery, Tim!
I see it not as trash but as a broken promise or dream. To deliberately move to such a town is a leap of faith, and most of that faith was misplaced. More dreams were destroyed than granted here, and this image of rust and residue is an apt symbol.