I have the prettiest grey arab but he has ugly black marks on his shoulders from the rug rubbing. He wears a bib under the rug and no bindings or anything touch where the rug is rubbing. He is clean as is the rug and bib so it is not from grit or anything. I have also tried baby powder on his shoulders everyday but it has made no difference. I was just wondering if many other people have this problem and what they do to fix or even just help the problem. Any suggestions would be appreciated.