I plan to market my Idletime in the near future and noted the thread about not using pressure washers on the rubber roof. May a pressure washer be used on other parts of the RV? Is Simple Green too powerful a soap to use on the rubber roof? The caulking on the seams has turned dark due to collecting dirt and road grime. Is there a way to clean that? I have used automotive liquid wax in the past. Is this OK?