Removing black streaks
 

I read this on another camping forum,haven't tried any of these. Try any of these on a small area before using. Spray'n wash,Dow scrubbing bubblescleaner,WD-40,diluted tide laundry soap,castrol super clean,Hot water and peroxide, and GoJo hand cleaner. Be careful with any of these products around decals/graphics. Happy scrubbing.