I hate to share this, but 65 years of storing guns, in and out of safes in the DC area has resulted in no rust or condensation with no help from rust inhibitors. Maybe I'm just lucky. For several years, my only safe was on a carport, unprotected from weather and still no damage to the guns. I have never used a light or anything else. Now I use a dehumidifier and empty it daily, still no sign of rust or condensation.