Well bringing back a old thread.
I did not do the clay bar. Instead I went out and bought meguiars #50. This stuff works really really well. Easy to put on it cleans very well removed some old bugs and the odd black streak. Came off just as easy as it goes on. And even made the black window frames and plastic bits look like new.
My tralier is 20ft I only used a half bottle. Took the wife and me about 3hrs to do the whole tralier.
I recommend this product.
2006 chevy colorado xtream.
Holiday Rambler 187qb.