Just a note: be careful with most products that are advertised as household anti-mold treatments. For the most part they're just bleach with a surfficant to help it stick around better.
edit: you have this segregated from your other guns, right? If it came with dead bugs and suspected mold I wouldn't want it near the rest of my collection until I was 100% sure whatever crud it has isn't going to spread. All it takes is a few mold spores hanging around in your safe and a power failure on a humid day and you've got a real problem on your hands.