I gave up. Had it professionally detailed back in Aug of '07 when I bought the car to get rid of the miriad of swirl marks. Kevin (GTAinDetail - Here are my pics from that day. http://gtaindetail.com/pics/vette082107/) did an awesome job. I'm going to have him do it again this spring when the car comes out of storage. But I use warm water and soap. Meguirs usually does the trick. Black is just too much work to keep clean.