Recently I got into a discussion with a long time stamp collecting customer of our's who recently got started into coin collecting. He asked me about coin toning, its causes and what can be done about it. So thought it would be nice to share with everyone who doesn't understand why this occurs.
Toning is a natural process that coin collectors frequently encounter. After all, coins are made of metal, and virtually all metals will corrode under the right environmental conditions. As the chemistry of the surface metal changes, so does the coin's color. With some metals it happens faster than others. The key to keeping your coins as beautiful as the day you acquired them lies in your coin storage and how you store them.
The first line of defense is the coin holder itself which helps prevent the metal from interacting with the environment. Plastic coin capsules that are virtually airtight offer the greatest protection against the environment and oxidizing agents. Self sealing plastic flips offer the next level of protection that seals out much of the local environment. Clear plastic flips with open pockets still offer good protection for the coin, but still leave the coin more susceptible to the environment around them.
It is the surrounding environment that you store these coins, no matter what they are in, that will determine the accelerated oxidation. The sulfur and organic compounds in cardboard can tone metals quickly. If you leave a silver or copper coin sitting in a cardboard box, you are likely to see color changes. When not protected from the natural surroundings, a coin can begin to oxidize immediately when stored within cardboard. High humidity and temperature also will hasten the toning process. Basements, attics and garages, with their extreme temperatures, are not good places for your coins. Adding silica desiccant gels to your storage container, and changing them out every year is also a way to help your coins avoid susceptibility to the humidity.
Using common sense and high quality coin holders from SAFE, can keep your coins as fresh and beautiful as they are today. Be confident that SAFE coin holders and coin capsules offer optimum protection from the environment. And remember to avoid keeping your coins near materials containing volatile oxidizing compounds and store your collection in a stable environment.
