When I purchased my previous motor home, I received some literature from the rubber roof manufacturer. They recommended using Murphy's Oil Soap to clean the roof. I used it for the several years I owned that motor home. It seemed to work extremely well and was very mild, not harsh like some of the other cleaning products mentioned. If you use it, just be aware that when you rinse it off, a light residue will run down the sides of the vehicle. However, this residue will wash off easily when you wash the sides of the vehicle. Good luck!