I bought a gun safe from a bankrupt weed shop in Colorado. Bought it sight unseen (other than photos) from an online auction. When I picked it up, the interior reeked to high heaven (pun intented) of weed. Left the safe door open in my garage for a few weeks, hoping it would air out. No dice. So I bought a $50 ozone generator off amazon, and that did the trick after running for just a few hours. I've had it closed for a few months with my guns and other valuables, and the smell has not returned. Even papers that are in there have not taken on any weed smell. It's what car dealerships use to get any and all smells out of used card.