It depends on what you mean by polishing, as in, do you want them to be mirror finished, or something less than that? And also, what level of finish you're starting at makes a huge difference.
As, for example, for lifeline stanchions, unless they're horrid, Flitz Metal Polish will bring them back to mirror bright pretty easily. But if you're talking about serious
corrosion, or
parts which were never shined up at all after they were fabricated, then that's a whole different task & "set of tools".