Just bought a Winchester 70 classic stainless in 30-06 for $425 score. Bad news it has black spots all over the barrel from the forend forward looks like mold but I assume it is rust spots, doesn't come off with oil. I made them take it completely apart to inspect. Action looks fine and barrel inside stock looks fine and inside the barrel looks good also. Will need a new crown but otherwise pretty good shape except these spots. Thought worst case I could sand it down and then cerekote the whole rifle. Has anyone had any experience with this before and know what might remove them?