Welcome to JOF
When it comes to cleaning products I'm sure everyone has their favorites. I use a name brand Wash & Wax for normal washing, and if it's extra dirty I use Dawn dish soap to get off the stubborn "stuff".
For the black streaks on the side of the TT there are a number of good RV "Black Streak Remover" products on the market that do a good job.
Bob
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2016 GM 2500HD 6.0L/4.10
2018 Jay Flight 24RBS
2002 GM 2500HD 6.0L/4:10 (retired)
2005 Jayco Eagle 278FBS (retired)
1999 Jayco Eagle 246FB (retired)
Reese HP Dual Cam (Strait-Line)