10,000 ways. Lasers, scotch brite pads, sandpaper, dremel tool with felt head and polish, complex, simple, everywhere in between.
On and on and on and on.
Then, a light coat of oil, grease, lard, on and on and on and on, whatever, you want to use, to protect it. Including paint, clear coat, cerakote, dipping and so on.
Then of course, you can manage the moisture in the area in which you store these to help prevent it, and there are 10,000 more ways to do this.
I'd hit it with my Dremel, then a tiny bit of battle born grease, which I like to use for about everything now. Scotch brite pad and the same, an oil or grease, would do well too and be cheaper.
I also still like hitting my guns with hornady one shot and wiping them down for a protectant. I find G96 and EEZOX are great too.
A ton of ways to skin this cat.