Thetford's Premium RV Black Streak & Bug Remover works to effectively remove black streaks, sun-baked bugs, and other tough soils.Specially created to work on RVs, boats, cars, trucks, vans, snowmobiles, ATVs, and any other vehicles, the formula is safe on RVs, gel coats, fiberglass, decals, and painted aluminum. More than that, you won't have to worry about damaging the seals around the windows, and is 100% biodegradable and non-flammable. Because this is an aggressive cleaner that uses alkaline detergents, it's best if you spot test all surfaces, especially on old/ weathered vehicles. Make sure the surface is clean before applying the product with a clean cloth or a sponge, and rinse with water immediately after. For best results, try using the product in shade.