I have copied and pasted the following from my previous post:
I've tried lots of different cleaners and all seem to under perform. I finally read the manufacturers literature (Alpha Systems), that came with our 2008, 313RKS. They suggest to use products such as Comet or Spic n Span on the EPDM rubber. I tried the Comet and could not believe how it cleaned the roof. Instead of a brush I used a piece of floor polisher pad, by hand. It helps to release the dirt from the surface without affecting the rubber. Make sure that you rinse well to prevent the residue from the Comet from drying and leaving a white film. The roof is white again for a while!
As for putting a protective product on after cleaning, there is a product called Protect All, sold at Camping World, that is recommended by Alpha Systems, according to the statements on the Protect All web sight. Just Google the name and it is all there. I use the product, applying it with a sponge, by hand , in order to reach the sides of the EPDM that roll over the edge of the roof (slide roofs included) and keep it off the fiberglass sides and windows. It is a clear milky coloured liquid that dries clear.
We have extremes of heat , cold and snow. I'm hoping it will prolong the good condition of the roof, having it act as a barrier, preventing the ice and snow from getting a good grip on the surface and causing damage. I clean and seal the roof twice a year, Spring and Fall.
Hope this long winded info helps you out Folks
Married To The Navigator
2005 Red GMC Duramax 4X4 HD Crew Cab
4" Magnaflow, Banks Air Intake
Firestone Ride Rite Air Springs