I get a little paranoid when using sandpaper on the trailer. But the fact is the corrosion is looking better, probably will never be perfect, but better is good.
I wet sanded today with 1000 and 1500 grit. Used Aluma Bright acid to wash it again, restricting my work to one panel, to use as a learning curve.
Washed with mild car wash and water afterwards.
I will try some polish on that area tomorrow to see if more sanding is needed or if it is coming to the point where I will be happy with it.