I second Steve Dion's url link to Spotless Stainless.
Steel wool wouldn't be a good choice (actually on bottom of the list for almost everything on a boat). Shreds of it get embedded in crevices and then rust real quick, which the leaches into gelcoat, paint and everything. Further, for stainless steel you want to avoid scratching surface which removes the protective surface layer. And the fine scratching from the steel wool rubbing will make it difficult to ever again get a bright shiny finish on your railing.
Just by chance, my first time order of Spotless Stainless arrived on Wednesday and I got to using it the same day. The stuff does what the website describes. My results were just like the before/after pictures on the website. On my boat, rust and discoloration in impossible to polish (with normal SS polishes) areas like railing weld crevices and tight spots at the base of my stanchions are now shiny and rust free without any polishing. Spotless Stainless did the same to the SS on my blocks, boom bails, and shackles and the like. A second application on Thursday removed virtually all of the remaining rust/discoloration in the real bad spots. The website claims that the citric acid component in Spotless Stainless promotes a chemical reaction to establish an oxide barrier coating on marine grade stainless steel surfaces; so future re-rusting will be inhibited. Time will tell on this, but just for the rust/discoloration removal and brightening results that I got, this is a really good product. Also do a search for Maine Sails posts about Spotless Stainless.