black streaks & polish

welshboy

Hi all, 

I have just picked up a bailey ranger 2006 and after washing I have some black marks down the van and discoloured / dull patches, I have used blue diamond black streak remover but you can still see them. I also tried Fenwicks caravan cleaner as a streak
remover but with no great results. Any ideas? would you t-cut it?



Best polish advice to please.

thank you