Black Streak Eliminator is safe to use on fiberglass, metal and painted surfaces and will not remove durable waxes or sealants.Black streaks running down the sides of boats and RVs are caused by run-off from the dirt, mildew, grime, bird droppings, fallen leaves and other contaminants that accumulate, then decay and are washed off the roofs and bimini tops during light rains and heavy dew.