Black streaks down the sides of your rig are caused by run-off from the dirt, bird droppings, fallen leaves and other stuff that decays and is washed off the roof of your RV during light rains and heavy dew. Regular cleaning of your roof, especially just before the rainy season starts, will go a long way toward eliminating the cause of black streaks.
You may want to clean your RV’s roof more often than three or four times a year if you regularly park under sap dripping trees, fruit trees, trees that attract a large bird population or places where harsh environmental fall-out may settle on your roof. If allowed to stay on your rig for an extended period of time these conditions may result in unremoveable stains.
Washing the sides of your RV with a good wash & wax product regularly will do a lot to keep black streak causing stuff from the roof building up on the sides of the rig.
If you already have a black streak problem try WD-40 before you go out and buy something special. You’ll have to wash with regular soap and water after using WD-40.
Beware of some black streak products.. they may permanently remove the gloss from fiberglass RVs. Always test a small, out-of-the-way place first. Gel Gloss will clean black streaks from most fiberglass.
Some people use common bug and tar remover. Turtle Wax makes one as do lots of other companies. Again try it on a small out-of-the-way place first.
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