You might consider this. Before we started full-timing, where I parked our rig at our house, one side was protected from the afternoon sun. Upon returning from a trip, I would wash the entire rig, then wax the side that was to be exposed to the morning sun. I would put the wax on & leave it on. When we got ready to take her on the next trip, I would wash the entire unit, thereby removing said wax. Upon return, I would do the same, but with the other side now facing sun exposure. When we sold the rig, she was 12 years old. Looked brand new, even after all those years in the So Cal sun.