My (now 45-ish) baby girl was diapered with old-time cotton diapers. I still have a few of them, squirted with 3-in-One oil, used to wipe down any firearm handled before putting it away in a safe. Keep the diapers in a zip-lok bag hanging inside the “safe” door.
But Each Gun is kept within it’s own, cheap “Hard-Case” by Flambeau or Plano for further protection, especially protection from being banged-around, and dozens more can be uniformly stacked/stored within each “safe” that way instead of trying to figure out how 15 guns can be kept in a “safe” which claims to be a 36-gun “safe” with 36-grooves cut into particle-board. (pawn-shops and garage-sales commonly have the hard-plastic cases for $10 or less. I toss out gun “safes” interiors because all they do is take-up room and complicate matters. I only keep a top-shelf for accy’s, pistols, paperwork, etc)
I keep a large qt-jar of “dessicant crystals” inside the “safe” with a wire-screen top, and which I spread the crystals out onto a cookie sheet once/year and bake until the crystals turn from pink back to blue…. I think that’s probably just rearranging Titanic deck-chairs….but it gives me something to do.
It’s important a proper rubber seal is maintained on the door. Also, seal up any entrance-holes intended for lighting or bolting-down to the floor…because any flooding will use that to enter the “safe” …(the word is a farce… they should be called “Child-resistant cabinets”. The better ones take a little more time to break into…but that is all they really do, and unless they are kept in a concrete, fire-resistant bldg ..they are not really “fire-proof”.)
They satisfy insurance agents and local laws regarding weapons and children however.
