Actually the warm rod suggestion is a good one, but you didn't say whether you had a gun safe or not? If you use desiccant, it will get consumed rather quickly in a humid environment unless it is sealed in with the guns somehow. You would want some sort of giant Pelican case with O-ring seal, or maybe a 20 mm ammo can for the handguns.
If you are in a regular closet, don't allow bare wood, cloth or paper or anything else that holds water up against the gun metal. You can cut white epanded polystyrene up to form gun racks that won't wet the metal. Get hold of a 240 volt light bulb, make a caged base for it so you can safely set it on the floor of your closet leave it on all the time. That will warm things up to prevent condensation. If the bulb makes things too warm, put a rectifier diode in series with it so it runs on 60 V. You can get a low wattage 115 v computer fan to stir the air, if you really want to get fancy?
Nick