Thanks to everyone's comments in the preceeding posts(I don't know how to do the multi quote thing, and thank everyone with one post)
After we did some camping in the Tear Drop, I needed to fix the aluminum skin. There were scratch marks and stains that needed to be cleaned off. I did a acid wash with a weakened solution of Muratic acid. That was not a good idea. I wound up with more stains than what I had at first.
In this photo you can see where the acid concentrated below the rear galley vent.
This was how I got rid of the marks and stains. I started with a 120 grit aluminum oxide sand paper and my 1/4 sheet palm sander. Then I used a 180 grit sandpaper, and then a green scotch brite pad. I then used the same green scotch brite pad and did some final hand sanding in a circular pattern. By doing the final sanding by hand, I can blend in future scratches in with just the green scotch brite pad and avoid using the 120 and 180 grit steps (unless it's a big scratch or mark). By having lighter and heaver areas of sanding on the skin, and random circular patterns it beaks up most of the areas on the aluminum and hides most of the imperfections.
I then cleaned off the aluminum skin and applied a coat of mineral oil.
The aluminum skin is not a maintenance free covering for Tear Drops, but with a few hours each year after the camping season, it is pretty close.The major re- doing the skin on this tear took me about 8 hours to do.
My next posts will probably be about Silver Space ship #2, which is in the design phase right now. I will be 200 lbs lighter, with the use of fiberglass instead of wood, and a lighter metal frame. (I really overbuilt the trailer frame on this build).