I keep an EVA Dry dehumidifier in my safe. I like them because they're easy to dry out, just unfold the plug on the back and plug into an outlet. Their built in heater will do the job, kinda like recharging a battery. They all have an indicator on the front to show when they need recharging. Not as cheap as the desiccant tubs but a lot less bother than pouring the desiccant out of them, baking it, cooling the stuff and refilling.