I wish I'd taken pictures.
The '04 21FB was looking a little "green", we're in our 8th year with it and it's been a really good unit for us.
We mostly camp off grid in the Pacific Northwest (read damp) and the exterior was looking pretty off white. It was getting to the point that if we weren't sure where we were parked we could have missed it in the background bush...
The self serve car wash with the foaming brush just wasn't cutting it for getting the film off the finish.
I picked up a jug of 30 Second cleaner and a pressure pump sprayer and waited for good weather. Late last month it was dry and warm enough to get at it.
HOLY COW!!! It works like a hot damn. The trailer is white again. The propane tank cover is dazzling and the spare tire cover doesn't look like a blue cheese wheel anymore.
I highly recommend this for the exterior cleaning. 90 minutes and it doesn't look like an 18 year old trailer any more. Well, except for the faded peeling decal swoops that are being removed at my earliest opportunity.