Wife's new car has all leather interior. Knife clip rubbed the steering wheel as I was getting in which roughed up an area about 1/4" wide and 2" long. worked it with mink oil (paste) and a steel bar. Got it about 3/4ths out, much better than before, but would like to smooth it back to original. Please give me some suggestions. Meanwhile I'll occasionally hit it again withe the mink oil and steel.