This thread is diving me crazy, my brain is spinning in my head and I keep coming back to it. There is a lot of knowledge on this Forum and maybe with everyone's ideas we just might be able to come up with a solution. This my Idea and experienceses: I know for a fact that white plastic or rubber is not ultraviolet resistance, it will break down very rapidly, black plastic or rubber is more durable and will with stand ultraviolet rays for a longer period of time. Example: Look at your A/C unit that is out side that's called the condenser, you will see two copper lines, one is small in diameter and the copper is exposed the other on is larger and is insulated. They both should run right next to each other along with the thermostat wire, all three components are held together with cable straps, because these three components are out side in the elements the cable straps should be black, if they are white and have some age on them then they are most like starting to break down some may have a yellow tint and powdery look. When white plastic or rubber breaks down it becomes powdery, if you take a damp dark rag and go over the rubber area before washing your camper you might fined that the rag will pick up a white residue form around the windows or any where else. Once the residue is removed the surface is now very porous and will allow dirt and moisture to settle in the nooks and crannies and in bed themselves deep in the rubber, then the next thing you know you are cleaning the crap out of it with chemicals and or a brush which I believe maybe making matters worse then leaving it unprotected. This is what I am going to try, once I get the discoloration off, then I am going to apply a small amount of Vaseline around the windows to see if it will soak in. The reason for this madness is because this is something I do every year two time in the season with all of the rubber seals on my swimming pool filter system. I have the same seals on the filter that I started with in 1985 and have not replaced one yet and of course I do not have any leaks at this time. The seals are black but they are exposed to chemicals and chemicals dry out rubber seals. Vaseline repels water and chemicals from reaching the rubber surface. So why not try this on the white rubber on an RV? other wise it all will have to be replaced. Please I welcome the Pros and Con's and more suggestion. Maybe we all can pull together and get some kind of solution to help everyone with this ugly mess. One other thing, have you notice that the rubber around the windows where they are pieced together are shrinking and are leaving gaps between each other?