just about to order some silica gel and i see that it comes in many forms ,steel canister , gel unit in aluminum , unit in cardboard and then their is the single pack gel or Clay Desiccant ... which one should i buy as i am going to eventually put the coin in safety deposit box but for now they are in the 20 dollar cheap metal lockbox , and on another note ....in the winter here in nyc the heat is mostly steam heat if anyone knows is this a bad thing for coins ,mostly presidential dollars , state quarters and wheat penny and if so what can i do to help ... THANKS everyone and HOWDY TO ALL :hail:
Humid and heat is always bad for coins, and therefore steam heat is definately not good to the coins although silica gel is definately a good idea. Most silica gels are ok as long as you don't get those which absorb moistures and convert them to liquid and if those leak, that's nasty...
I highly recommend the kind that has a color indicator that tells you when it needs recharging so you don't have to guess. For larger spaces, like a safe or a large storage box, I've found the self-regenerating units Eva-dry EDV-500 Renewable Wireless Mini Dehumidifer by Eva-Dry most convenient. When the indicator turns pink, you just plug the unit in overnight and it heats up, driving off the humidity. They're considerably more expensive, but much less trouble than having to bake the canisters in the oven. Interestingly, I have found that sealing the canisters in a ziplock plastic bag, doesn't completely protect them from absorbing moisture. After a few weeks, the indicators turn pink. Therefore, you can't count on ziplock bags to keep things dry indefinitely.
