Ive used car wash soap AND then dish soap which is a lot stronger. I plan to fully wax it too but cant even get the grunge off. Its not terrible, but from top to bottom, it has dark/black/grey marks from water dripping down the sides on the bright white trailer. It cant even be scrubbed off with a cloth and soap. What is it or how can it be cleaned off? Is there something besides automotive stuff to use? i have tons of meguiars waxes and polishes. I think the trailer came non-waxed so id like to clean it to get something on it finally, its only 5~ months old or less.