Noticed some surface rust on my most prized shotgun after it sat unused in the safe for only 2 weeks. The safe is in my air conditioned house. I don't belive the safe is air tight but not sure. It IS fire proof for 45 minutes or so. Question: Can I use one of those dehumidifiers that use the granular material in their own plastic bucket? I know they work on my boat to help dehumidify but for some reason thought I read once about them not being a good idea in safes. Thanks.