I have a National gun safe which I believe is one of the best built. I have a Golden Rod heater installed. Since my safe is in the basement I keep an eye on humidity and dampness. The Golden Rod seems to be doing the job. The safe does have a vent hole in the top to vent. There are other things (silica gel packs and cannisters) that can also be used. When ever one of my guns are used or handled they are always wiped down with a silicon gun cloth. So far all this is
working for me and I have not noticed any rust forming on anything. I also believe that this safe is very secure
Hope this helps
We preserve our freedoms by using four boxes: soap,ballot,jury, and cartridge.