Hmmm well i have worked all day cleaning approx 40 semi's Using Moerman liquidator with Razr red facelift rubber. One min it seems great then for no apparent reason it leaves fine lines on the glass. If i use the rubber in a standard unger channel the are no problems at all. I have been using unger channels for close on 30 years with either pulex or unger soft rubber and very rarely have to do any detailing. I honestly cannot see what all the fuss is about with the liquidator.