Re: aluminum pitting
You could do what I did, if removal is an option. Take the frame to a Powder Coater. They will sandblast the frame, weld in any cracks or large damaged areas, and then "paint" it whatever color you want, including chrome or an anodize appearing finish.
I did mine in white and it looked really neat. Sorry no pictures available.
This process also helps protect the surface and reduce the likely hood of having to do it again.