What's the best way to store a non-slabbed collection of coins of all types of metals? I currently have then in 2x2s in a cardboard holder in my safe. The safe has a dehumidifier. Is this good enough for long term storage?
It's not bad, depending on the effectiveness of the dehumidifier. I subscribe to the theory that there is no single best method for all coins. Everything is metal-dependent.
I understand completely. Just wanted to make sure I wasn't doing anything to harm them or missing out on something that I could be doing to better preserve them since they are of all different metals.
There is definitely a better way to store them than using cardboard 2x2s. Paper in almost all of it's forms is harmful to coins because paper has a high sulfur content. So you never want to keep paper (and cardboard is paper) anywhere near your coins when storing them. And that means not in the safe at all. But 2x2s have other issues besides just being made of cardboard. The thin mylar cover does a very poor job of protecting the coins, they can be scratched and or get additional contact marks right through the mylar. And, 2x2s also put of what i called cardboard dust, small particles of cardboard that can get onto the coins and hairline or scratch them. The safe and the dehumidifier is fine, but the best way to protect them is to use hard plastic coin holders. Sure, they are more expensive, but if you want to protect them that is the way to go. They make several different kinds and the Air-Tite brand name is the least expensive. But all of them work equally as well.
Mylar flips are good too. Just make sure they haven't been treated with PVC, because that will do more harm than a 2X2. I fortunately live in a state in the western U.S., so humidity isn't a problem in any season. I lived in Wisconsin for a couple of years, and summers could be brutal humidty-wise.
Do a forum search using - coin storage - as the key words and put my user name in the posted by box, then click on search. That will bring up a lot of threads on the subject of proper coin storage for you to read.
Myalr flips also have their own problems. The edges of them are so sharp that they can scratch coins when you put them into or take them out of the flips. And, the plastic can and will cause additional wear on the coins as the coins move around inside the flips.
You'd be amazed at how many people do not see it that way ! To my way of thinking, if a coin is worthy of being in your collection then it is worth you doing the best you can to protect it.
You must use a different coin of mylar flip. The ones I use don't have sharp edges, and when they are folded, the friction on the rim holds the coin in place. If they were so bad, why would the TPG firms use them for people to submit coins in?
All mylar flips have sharp edges, which is exactly why dealers don't use them. Almost all dealers use the soft flips, the ones that contain PVC, when they sell their coins for that very reason. And they don't worry about the PVC because they know it takes a period of time for it to become a problem. And because they know that almost all collectors are aware of this as well so they will remove the coins from the soft flips once they receive them. As for the TPGs, they don't specifically recommend mylar flips when submitting coins. They just tell you to use flips. And if you don't, the the TPG themselves will put the coins into a soft flip before they give them to the graders. The TPGs don't use mylar flips either for the same dealers don't use them.
From NGC's website: "Preparing Coins for Submission Place raw coins up to 40.6 mm in diameter in 63.5 x 63.5 mm non-PVC plastic flips. Use larger flips for larger coins. Coins should insert easily into a flip. Placing a coin into a flip that is too small may result in damage to the coin." Now let's parse that. They specifically say NO PVC-containing flips, but they do NOT say "mylar", per se, which is the most commonly available non-PVC type. What do they SUPPLY at shows? 2.5"x2.5" flips that are NEITHER PVC nor Mylar, a fairly difficult to find type.
My non-slabbed coins are in Air Tites. They can be a bear to open once sealed but do provide good protection.
I'm very partial to the Lighthouse plastic containers. They are easy to open and close without worry about launching or touching the coin, and are clear enough to photograph through. Plus, they are very cheap.
When storing silver, museum conservators wrap silver in sulfur-free tissue paper and store in a tight sealed polyethylene bag. Activated charcoal is sometimes used to absorb sulfur by placing it in the bag but not in direct contact with the object. Likewise, Pacific Silver Cloth has also been used by museums to prevent tarnishing. Thanks to https://en.wikipedia.org/wiki/Conservation_and_restoration_of_silver_objects
Intercept shield makes good 2x2 plastic holders with soft inserts for loose coins and boxes with sleaves for slabs. They also have large storage boxes to put the other boxes in. Storage becomes an investment in itself if you want to do it right.
Another way I like to store coins that I don't want to be exposed to air changes or the storage container is to place them in polybags -without a ziplock closure, fold it over, then place that in a mylar flip. This stores the coin very safely until I decide what to do with it.
