When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Most RV supply shops will have Black Streak Remover. There are probably several brands. We use it occasionally on our fiberglass sided trailer and it works fine.
Every year or two wouldn't hurt to wax the trailer with some auto wax. Helps make dirt easier to remove.
Yet? Why, yours doesn't have the flaming problem? :P
I hate smokers... trucks or folks! Especially the jackass driving the Dodge with "stacks"... which blew directly into their horse trailer's open window. Nice one, dummy.
The best thing I've found for removing the black streaks from fiberglass trailer panels is a cheap brand of glass cleaner. It contains ammonia and it takes the black stuff as well as any bug guts off.
Just spray areas about 3 feet square liberally with the glass cleaner and use paper towels immediately to remove the soil. Start at the top and work down.
I've tried the so-called black streak remover with very unsatisfactory results. We use glass cleaner from the dollar store.
On the front fiberglass cap after I have cleaned it of black streaks and bug guts, I apply a coat of Turtle wax and buff to a shine. That prevents other soil and bug guts from adhering for a good while.
I'm not one to spend more time, effort or money than I have to at any task and this works for me. Give it a try.
if you get black streak remover or bleach be sure to follow the directions dont let it sit too long or dry that stuff sure can eat paint & decals real quick.
Ok nobody mentioned the best way to keep them from coming back. The biggest secret to the streaks is to keep the roof clean. Think about this, all the dust and fallout crap in the air sits on the roof of your trailer after a rain all that gets washed down the sides.
The best chemical that I have seen is called Awesome, you can find it at the dollar store.