How To Store Your Coins and Collectable Coin Collections.
There is a kind of Hippocratic Oath used implicitly among coin collectors ...
First, above all do no harm
Rules on cleaning coins are well-known in collecting circles, even though there's continued debate about how and when.
Despite that there's a general conscensus on how to store coins.
To avoid the damaging effects of oxidation, finger oil, scrapes, etc, coins should at least be stored in Mylar plastic containers, one coin per compartment. They come in a variety of styles.
Inexpensive Mylar-lined cardboard holders can be purchased, which have a small, round cut-out for placing the coin so it can be held up and seen from either side. They come in a form sometimes called two-by-two's and they are often 2 inches by 2 inches.
How to Store Coins - Methods and Materials
Coin holders are sheets that will hold several coins, with each in its own separate area. Some have small, individual sleeves that will hold one coin each. Several styles have holes punched in the edge so that coins can be stored in a binder, but these are not ideal. Coins should be stored so they can be displayed.
Coin Cabinets, ranging from small, glass and wood cigar-box style holders to large, floor-standing Chippendale types, can be bought to hold and show off your collection. The more expensive types are nearly air-tight and some even have archival-style dehumidifiers.
Aged mahogany or rosewood both make excellent wooden cabinets. You should avoid any wooden cabinet, such as oak, that emits organic compounds into the interior. Many types of tree, long after being chopped down and even when not coated with varnish, will produce volatile, organic compounds. Some of those compounds are harmful to coins.
Many collectors, for that reason, will recommend a metal cabinet instead. Several styles exist, some with a coating that helps to prevent scratching and oxidation. Plastic or polystyrene containers are also available, though they rarely display as nicely.
Whichever style of cabinet you get, apart from those with in-built dehumidifiers, it's helpful to have a supply of silica gel packages or other desiccant. They absorb moisture that contributes greatly to oxidation.
Some collectors will coat the coins with vegetable oil or wax before storing, but these practices are controversial.
Oil can attract contaminants and wax may give a false sense of security, since it can easily wear off or obscure the view.
How not to store coins - Coin Storage Methods to Avoid
Beyond what to do or use, there are several things to avoid.
While avoiding exposure to air is good, it's not true that any kind of packaging is better than none. PVC (polyvinyl chloride) sleeves are generally not recommended. They can cause the coins surface to become coated with a greenish sludge that is harmful and difficult to remove cleanly.
Though displaying coins is preferable, storing them away is sometimes necessary. Paper envelopes can be used for this, but avoid standard office supplies. Get envelopes specifically made for coin storage. The sulphuric acid in ordinary paper can damage coins, especially coins containing copper.
Never store collectible coins in any kind of bulk container
Such as penny rolls, plastic tubes, etc. This leads to scratching and denting and doesn't keep out harmful air.
Specially-made sealed containers that hold a collectible coin are best, though they add to the up-front cost of the coin. In the long-run, however, they will keep your coin in good condition for long term storage and display.