Pistons/reconditioning

I'm in the process of cleaning my pistons. Apparently, my engine guy just dipped them in some sort of degreaser. There is some white, powdery residue left in spots, and some light pitting in other spots. This got me to thinking....
First of all, is there any sort of aluminum cleaner I could dip these things in to really get them clean? On some of the aircraft parts (airframe parts, not engine parts) I clean at work, we dip them in DuPont metal etch/cleaning solution, which gets the aluminum looking like brand new. I believe it is a form of phosphoric acid. Any reason why I wouldn't want to use something like this? I could also use ScotchBrite, which will leave a shinier surface. I'm sure it would clean them up well, but not sure if it would weaken the metal.
Then I got to thinking about the mild pitting on the piston skirts (below the ring grooves) and started wondering, again. As a reloader, I know they make spray-on Molycoat for bullets (those are the black-tipped ones) that is an extreme pressure/heat resistant coating. Would there be any advantage or disadvantage to coating the skirts with something like this? Would it interfere with break-in? I'm using new rings with freshly-honed cylinders. I know some of the new pistons come with some sort of coating on them. Any insight would be appreciated.