Loaded question. Lots of discussions on this one. Just a few: Dawn, Spic-n-span, Comet, Purple Power, Murphy's Oil Soap, Tilex, and of course all of the known rubber roof cleaners from Thetford, Dicor, Full Timers, Protectall, etc., just to name a few.
I think everybody has their own preference or home brew for this. Somewhere in all of your paperwork should be something indicating what roof you have. Probably a dicor product. You can read in the paperwork on the roof, or go to their site and read up on what they say you can use. But, I've always found, whether Alpha or Dicor, some things they recommend really don't work that well.
John and Rebecca Dickson
Emma-7 / Little John-5 / Iva-1
Full Timing Again, Rev B
2013 Ford F-350 Lariat CC LB PSD
2015 SOB TT - With OC's Awning Poles (#8)
At least in Heaven, RVs will be perfect, and I won't have to keep fixing them.