We bought a motorhome a couple years ago and it was in perfect shape. One annoying thing, the roll out awning has a rust mark the width (15 feet)and about 4 inches high. I think it may have come from rolling it up wet. I have tried bleach and CLR but it won't come off. Of course it is in the white stripe not the brown! These awnings are $700 to $1000 and I don't really want to buy a new one when this one is only about 4 years old and in excellent condition. Please help. I couldn't find a camper site so thought there might be ideas here. Thanks in advance.