I been using FLITZ for years.. Blue runny paste comes in a tube.. Seems to pull out oxidation pretty good. Similar to Simichrome and Solvol Autosol. I once had a water stain on a brand new pipe.. Cleaned it with Solvol and it left fine scratches..FLITZ won't scratch silver, let alone chrome..
For really rough white powdery aluminum, I heard Marvel Mystery oil work, have not yet tried it.
But I think this thread started out with getting it smoother and ready for polish. ..not final polish.