Has anyone had any luck polishing out scratches in their windshields? Mine has scratches from the wiper arm from the previous owner. I have Bon-Ami and tried it in a small area without any significant improvement. Am I just not patient enough? What about some other mild abrasive? Pumice? I've heard of, but never seen jeweler's rouge, being used with some success (do you know where it can be purchased?). Thanks in advance. Paul