Handling, Storage, and Treatment of Gold Coins
How a collector or dealer treat his coins can greatly affect how well they hold their value. Metal is both more reactive and softer than most people would think. The human body contains many corrosive chemicals. Simply touching a coin in some cases can contribute to its deterioration. This is especially true of coins exhibiting mint luster or iridescent toning. Touching a bright copper surface with a sweaty thumb can easily result in the appearance of a dark thumbprint several weeks or months later. All this being said, it is easy to understand why the first lesson of coin collecting should be "Never touch a coin on its surface." If one needs to pick up a coin with bare skin, touch only its edge. In the case of proof coins, even greater precautions must be taken. The highly reflective surfaces are so sensitive that one should avoid even breathing directly on the coin. This will cause what coin collectors call "carbon spots," small black dots. Also, do not leave coins out unprotected where thy can be directly exposed to dust, sunlight, or changes in temperature.
Coins can be stored in many ways. One of the most convenient is the 2" square plastic "flips." These are transparent holders with two pockets, one to contain the coin, one to contain a cardboard ticket on which information can be recorded. It folds over on itself into a size 2" square. Originally they were made only of a PVC-formula plastic. This was particularly flexible and easy to work with, but eventually it would break down, depositing a green slime on the coins it contained. Today both the PVC formula and a new more inert Mylar formula are available. The Mylar type is prone to cracking, but so far has no been found to damage coins. The PVC type is still popular because it is more flexible, but is now usually used only by dealers and auction houses for temporary storage. Collectors usually repackage coins purchased in such holders before placing a coin into long-term storage.
Another common coin holder is the "two-by-two." This is a pair of cardboard squares with an adhering film of relatively inert plastic. The coin is sandwiched in between the two layers of plastic, and the two halves are stapled together. While this does not permit the coin to be removed and touched as easily as storage in flips, it does permit the coin to be viewed on both sides without opening the holder. It is important to remember that when you remove coins from these holders, be very careful not to accidentally scratch the coin on the exposed ends of the staples that may poke out if the holder is bulled apart. These careless staple scratches have ruined countless good coins.
Both flips and two-by-twos fit nicely into specially made boxes. They also fit into plastic pages designed to hold 20 or either holder. These are transparent and will fit into most of either holder. These are transparent and will fit into most looseleaf binders. It is important to remember not to place coins loose in these pages, as they are often of PVC plastic. Moreover, some of the thumb cuts are large enough for some coins to fall through.
There are many specialized coin albums and folders designed to not only store and exhibit a collection, but to guide the collector through it. Each coin in the series is individually labeled making their use extremely convenient. It is widely believed that one of the main resons coin collecting was able to catch on with the American middle class in the 1930's is the invention of the "penny board," a one-sheet predecessor of these modern coin folders and albums. Old albums and folders contained elements in the cardboard that would tone the coins, although actual corrosion was rare. Today this has been removed from most albums' composition.
This same phenomenon occurs with the long-term use of the orange-brown 2" coin envelopes, although it is less of a problem with those of other colors. The toning in this case is caused by sulfur in the paper.
Many new collectors ask, "How do I remove the toning?" While it can be done, it is not recommended. Though there are rare exceptions, it should generally be stated that one should never clean a coin! It is highly likely that more harm than good will result. Toning is actually part of the coin. It is molecularly bonded to the metal, and the only way to remove the toning is literally to remove part of the coin. This is a way most coin dips work, by means of a mild acid. Physical cleaning is even worse, as microscopic striations almost inevitably are cut into the coin's surface, even with something as mild as a tissue!
A cool, dry environment is best for storing a coin collection. Of course not everyone lives in such a climate. One common answer to this is to store a packet of silica gel in the same container as the coin collection. This is a desiccant and will absorb the mosture in the air. Packets can sometimes be obained at photo shops, or through your local coin dealer.