I need advice from you more experienced folks on the best way to keep your slide toppers clean as well as the best way to clean them. I can already see that these guys are going to need somewhat more care than the awning. What is the secret to keep the way from puddling on them while camping? They do not seem to be as tightly stretched when fully extended and of course they hold water which does lead to black spots when it dries. I think I read something about tennis balls as support a while back. Any suggestions??