Shurhold makes several washes and polishes and brushes and polishers. I use the spray and wipe, very easy to use and then polish. Got the tip from rv dealer in AL. Several folks sell it on INEt, get mine at Amazon. About two washes a year works great. Have heard of several roof washes, liquid Tide works great for me, does not clean out stains totally, but does lighten them up to medium gray.
Marriot2 on Wheels 2017 Flagstaff Classic 832 OKBS
2013 GMC Denali 6.6L 2500 HD DMAX w\Alison Trans
Pepper Pomeranian rescue 101 days as camping buddy
Days camped in FR, 2011 = 20, 2012 = 57, 2013 = 59
... 2014 = 39, 2015 = 52, 2016 = 68, 3 more planned