[LHaven]

The instructions I got were to clean only the old caulk with a rag dabbed in mineral spirits, and never touch it to the roof itself. Using the rag makes it quite easy to avoid the actual roofing. You can get mineral spirits anywhere on the road. When I have to patch the edge of the caulk at the roof material, which requires cleaning the roof material itself, dilute Simple Green with a water rinse is safe for that application. I don't do a two-step prep.

I carried a sample roll of Eternabond in my old rig. On a subzero morning in high Colorado, high winds slammed open one of my roof vents on which the strut had (unbeknown to us) disconnected itself. I ended up crawling on the roof in the freezing wind in order to tape the vent cover down to the rubber roof, figuring I would just cut the strip later. Although I did wash and wipe the dirt off both areas before applying the tape, I was quite disappointed at how easily it all lifted right off both the cover and the rubber roof, adhesive and all, when we got back home. Maybe it was the age of the roll, or the temperature at application. But I still carry a small roll for emergencies.