To commemorate various anniversaries and events, Japan Mint issues coin sets. Without careful treatment, however, these metal coins can discolor or become oxidized more easily. To keep your coin sets in good condition:

• Do not store your coins in a new cabinet or any new piece of furniture that has been painted or chemically treated.
• Do not store your coins together with volatile chemicals such as naphthalene or other insect repellents.
• Do not expose your coins to sunshine for many hours.
• Store your coins in a cool, dry space; avoid keeping them where temperature and humidity vary considerably.

The coins are encased to protect them from damage. Do not remove them from the case, since human skin oil can contaminate them, eventually causing discoloration. Also, even invisible scratches can accelerate discoloration.