Thanks for your advice. I got it from an ebay reputable powerseller. Looks like that most of her aged LV collections have more of less the same problem which make me confused too...It looks like the zipper pull is plated with a thin layer that now have chipped off. It can't be polished because it'll be more tarnished. Other mono bags like the speedy have solid brass hardware and can easily be polished, that's why I'm confused about your zipper pull. You could take it to a LV store and ask for zipper pull replacement quote.