I've inherited a collection of old coins from my grandfather and I want to take good care of them. Some are silver and others are copper, and I don't know if I should store them in plastic sleeves, special boxes, or what. Does anyone who collects coins tell me how they keep theirs in good condition?
The first thing is don't put the coins in regular plastic because a lot of plastics release acids that corrode the metal over time; you need coin storage sleeves that are PVC-free, the ones they sell at numismatic shops. Store them in a cool, dry place, away from humidity, ideally in an acid-free wooden or cardboard box, and avoid touching them with bare hands because sweat damages them too. If they already have rust or dirt on them, don't try cleaning them with anything abrasive; better to have a professional check them out before you try anything, because there are specific methods depending on the type of metal and the condition of the coin.
The key is keeping them dry and away from humid air, more than anything. I agree about the PVC-free plastic, but there's something important that often gets overlooked: even those special sleeves need to be in a hermetic container with desiccants (like silica gel) to control moisture. Silver coins naturally tarnish over time, that's normal, but copper is what suffers most from oxidation if there's humidity. If you store them in a wooden or metal box without extra protection, you're going to have problems! The best approach is to combine everything: acid-free sleeves + hermetic box + desiccants that you replace every six months, and you're set. Your inherited collection will be in perfect condition that way.
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