Recommendations for storing collector coins
Collector coins have to be stored in original packages (e.g. transparent capsules, representation boxes) in rooms where the temperature reaches 18–23°C and humidity is 45–55%. It is not allowed to store coins in humid, improperly ventilated and unheated places as well as on hot surfaces or near strong heat sources. Humidity, temperature fluctuations, dust and polluted air stimulates oxidation of the coin surface. Coins that are produced from precious metals (e.g. gold or silver) or other metals and their alloys are not resistant to mechanical damages. Therefore, it is not recommended to take such coins out from capsules, as their surface and shape can be damaged (including scratches, indentations or dents), which consequently reduces their numismatic value.
If it is necessary to remove a coin from its capsule, one must make sure to wear special gloves and take the coin only by its edge. Coins must not be held in hands and put on glass, plastic or other hard, unclean and wet surfaces. It is not recommended to keep coins outside their capsules for a long time, since some metals and their alloys are not resistant to long-term exposure to direct sunlight. Coins from silver and its alloys are sensitive to human sweat and environment that has Sulphur and Chlorine compounds (e.g. rubber or leather goods), as their surface may darken. Mercury and its salts, which can be found in cosmetics, are harmful to gold and gold-plated coins, as white spots may appear on the surface of such items.