Why are military coins improperly stored?

Although military coins are made of metal materials, they have a certain degree of hardness and seem to be hard to damage. Keeping coins is not easy. The quality of the coin is divided into 70 grades according to the American standard. The correct preservation method should slow down or stop the corrosion process of the coin, avoid being damaged, and try to maintain the original quality grade. So why are military coinsimproperly stored? The following is a detailed introduction.

Here is the content list:

Chemical stability of coin material

Atmospheric conditions for depositing coins and observation of coin contact

Packaging materials that come into contact with coins

Chemical stability of coin material

Generally speaking, gold is more corrosion-resistant than silver, and silver is more corrosion-resistant than copper, and metals such as zinc, aluminum, and iron are more easily corroded. For alloys, it sometimes depends on metals with more active chemical properties. For example, pure gold has a better stability. When copper is added to gold to form an alloy, coins are prone to black spots. But brass (copper-zinc alloy) is more resistant to corrosion in the atmosphere than pure copper. Polyvinyl chloride in the packaging material is harmful to coins. Polyvinyl chloride will gradually precipitate plasticizers to corrode the coins at room temperature, which can cause irreversible losses. Sufficient attention should be paid to this point, especially to copper and copper alloy coins. In foreign countries, in the early 1980s, the hazards of using polyvinyl chloride were widely recognized, and this material was eliminated in coin packaging, and polyethylene was used instead. Water vapor, sulfide, and carbon dioxide in the air are also very harmful to coins. For example, sulfur reacts with silver to form silver sulfide, which makes the surface of silver coins gray and black. Moisture in the air also accelerates the oxidation process of coins.

Atmospheric conditions for depositing coins and observation of coin contact

The water vapor, sulfide, and carbon dioxide in the air are also very harmful to coins. For example, sulfur reacts with silver to form silver sulfide, which makes the surface of silver coins gray and black. Moisture in the air also accelerates the oxidation process of coins. During the appreciation process, touch the bare coin with your hand, so that the sweat will leave fingerprints on the coin, and the saliva and dust in the air will fall on the coin. These attachments will accelerate the corrosion process of the coin.

Packaging materials that come into contact with coins

Although the vacuum package can isolate the air, the packaging material is in close contact with the surface of the coin, which may damage the coin

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