barkeepers friend and a toothbrush make for easy rust removal..best stuff on this earth for rust removal!!!!! nothing equal or better in my book--not even much elbow grease with barkeepers friend and toothbrush....is easy....
There is something I ve used on land, but it seems to keep its effect even when it rains. Ive used two different things. "Rust Treatment" (applied every 20 minutes) and "Extend"(applied every 2 minutes). When their last coat is appled, the rust will appear black, then aplly another coat in 24 hrs. Either has never rerusted and makes for a paintable surface. They both neutralize the rust. Probably leaving it natural is what I would do for rusting ss.
Ive found Rust Treatment in Home depot(paint dept) and Extend in the some auto parts stores (by the under coatings and other rust stuff). It's great stuff for small projects and spots ye want to catch early as inside light bulb sockets where rust inhibits. Make sure ye knock off the heavy rust on bigger projects.
I still use it and I will make a note to a carry few cans aboard.........Thanks for bringin it up.
Extend also comes in a jelly like Naval Jelly, but those make fer really messy job.
WD-40 displaces water(as a preventative -best when used before the rust starts)