I recently picked up an old Fromm Bros straight. I noticed some black spots on it that I thought were blemishes, but it turns out its some kind of corrosion. The problem is that there are several of these spots on the edge, and I as I sharpen, the little black spots turn into microchips as apparently the corrosion is completely through the edge. Is there anyway to get around the problem of sharpening this razor without turning a 5/8" into 4/8"?