I bought my lindy about 6 months ago, and been using it like once a month? Took it out today and realized the zippers looked tarnished. I have attached pictures. As you can see, the zipper is not shiny, it seems to have a coat of cloudy film over it. The rest of the hardware, I have checked, they are alright. Advices please! This is my one and only H bag. Thanks in adv!