I have a Sierra Sport and it has fiber glass sides, I use a recipe for washing windows and it comes out spotless with little or no effort. I also live in Las Vegas and the water normally leaves bad white rings. I mix up ingredients in 5 gallon bucket (about 4 gal) and use brush on a pole wash sides and windows all at the same time (10 to 12 feet wide at a time), then rinse thoroughly. Now the hard part, grab a drink and sit back and watch it dry, then show your friends how clean and streak free your RV is.
HERE'S A MAGICAL WAY TO CLEAN YOUR WINDOWS!!!
This is the best way EVER to clean your windows!!! No drying is needed, and you won't have any spots or
streaks on your window! You can clean 2 big sliding glass doors and 8 large windows in minutes!!!
Here are the ingredients you need to use
per 1/2 gal)
1/2 gallon warm water
1 Tablespoon of liquid "Jet Dry"
2-3 Tablespoons of liquid laundry detergent or dish washing soap
Mix all of the ingredients above. Spray your windows down with your hose to get them wet then
wipe or brush on the solution onto your windows, then immediately hose it off. That’s all there is
to it and you're done. The remaining water just sheets off and you don't need to dry it off!