Some roofs are not meant to be cleaned. The oxidized material acts as a protectant. Wash it off and it will oxidize again and again until you have no roof left. Read your owners manual.
Dawn dish washing soap is good for cleaning but only if you wax afterwards. Otherwise, use an automotive soap to wash the RV between waxes. I wax mine twice a year.
2016 Jayco Eagle 330RSTS = "Madame Maxime
Maxxis M8008 E rated Tires and 16" Wheel Upgrade
Dual A/C 15K BTU, 14K Equalizer WD hitch with SC
King Bed with Java Interior, (2X) Yamaha EF2000isV2
2012 Ram 4500, 6.7L Cummins Turbo Diesel, MegaCab = "Hagrid
8'x12' BMCM Stake Bed, Cabin Chassis, 2WD
360 degree Virtual Tour