Hi All, Since I started using run guard or the likes on my chest to prevent nipple chafing, I now get a circular brown stain on my running shirt where the nipples are. My guess is that its dust from running outside sticking to the sweaty area where the anti-chafe is. My problem is that these spots don't come out and now I have basically unusable running shirts (unless its dark out). Any tips for getting these out? Shouting out does not work. Pre-soaking doesn't work either.