There's a fair amount of grime on the camper, and I was really worried about how to clean it without scratching or otherwise ruining the anodized aluminum skin. Several people on Facebook (the Avion Restoration group page) recommended Bon Ami Orignal and a blue scrubby (no metal!)
I had to order the special Bon Ami from Amazon, but when it came David instantly tried it out and VOILA! Worked like a charm. Thank you Facebook community.
And that's all there is to it.
It's exciting that it took off even the "subtle" rust stains. I was afraid that it was some kind of irreversible chemical reaction; the stain seemed to part of the skin, not sitting on top of the skin.
In some spots, there is old caulk plus dirt. For those, David used a heat gun, Goo Gone, and a wooden scraper, followed by Bon Ami. You can see the results here (this is the street side exterior where the heater vent came out).