Since you live in a humid area, go to your local Ace hardware and get a can of LPS 3. It's a paralketone product that we used for (among other things) preventing corrosion in the bellies of aircraft.
I lived in south Florida for 40 years and used it on all my guns. It dries to a semi-soft viscous wax coating that seals against moisture and preserves both wood and steel. It cleans off easy at a later date, too. I moved to northern Arizona about 23 years ago, and I still use it as (believe it or not) we do have a humid season.
LPS 3 was a Godsend for me, as rust was ALWAYS a problem in Florida.