Recommendations for Properly Handling Precious Metal Coins
To protect coins from the damaging environmental factors (such as moisture, air pollution, sunlight, extreme temperatures, and other metals) and mechanical damage is not recommended to take them out of their capsules.
Coins should be stored in a closed container in a dark, dry and cool place (temperature 18–23°C, humidity 45–55%).
Sharp changes in temperature and moisture cause discoloration that devalues coins.
However, if it is necessary to take a coin out of the capsule, be sure to wear soft cotton gloves and hold the coin only by the edges, never by the face (to protect against finger smudges), above a soft towel or surface.
Never clean coins (polishing, abrasive cleaning etc.), as this can cause irreversible damage and scratches on the surface and reduce the value of coins than their uncleaned counterparts. If you feel bly about cleaning your coins, take them to a professional, who can determine the best course of action.
By not following these Recommendations, you put your coins at risk.