[JRTJH]

It's been my experience that once a EPDM or TPO roof membrane "yellows/stains" with age, nothing will make it look like new again. You can spend lots of time and effort trying, but those "black spots" simply turn to "gray spots" and the "ultra-bright glow" of a new roof won't return.

You can recoat the roof with one of several "after market products", some with a lifetime guarantee, some without. Many cost as much as a new roof, some less expensive. Even with them, once you park under trees in a campground for a season, your roof will take on the appearance it has right now.

So, with the knowledge that it will never "look like new again" just do a good cleaning on your roof, make sure it's "mechanically sound with no leaks and no deteriorated/damaged sealant and "keep on camping"....