I've had my natural chromexcel Indy boots for a little over a year now. In the last few months they've darkened considerably. But the worst is what happened on the toe. After riding my bike the last few times it appears that I've rubbed/scuffed the toe into a dark mess. It doesn't appear to be dirt, it's as if the oil from the leather has been darkened. Any idea if there is anything to do to fix it. Can Natural Chromex be stripped down? Or should I just retire them to lawn mowing boots?