My Father has a black Grand Prix GT. We have had it now for about 6mons. It has some minor swirls in it. We blame it on the drying towel because it is just lintless drying towel from Autozone. We also use a Lambswool wash mitt and then a chenille to wash the wheels and underside of the rocker panels. Any suggestions on what to use to wash it and dry it??????? Tks guys-----91