Been a while since I ventured to the ol gun safe, never had any issues with moisture before however I noticed on guns with muzzle breaks and flash hiders the copper residue turned a nice shade of lady liberty. Nothing a good scrub didn't remove and all the rifles got a deep clean and rub down just to be safe. That copper fouling can get in some cracks and crevices that's not normally hit with a regular clean. Shotguns and rifles that only shoot lead rounds were obviously unaffected this time. Lots of moisture and humidity happening these days.