Storing your Coins - Part 2: What not to do
Before tackling these competing priorities, it is useful to set out some of the things we are trying to avoiding in greater detail. So what are the “wrong ways” to store coins noted in Part 1?
Don’t store coins in bulk
Yes, I’m talking about that old shoe box at the back of the sock drawer which your grandfather used to house his collection, with hundreds of coins packed in there like it was a miniature pirate chest. This rule perhaps doesn’t matter so much for collections of scrappy well circulated and common coins. But it certainly applies to anything better. Not only will coins stored this way scratch and ding each other, but they are exposed to chemicals and moisture in the atmosphere, and worse, rampaging toddlers. Further, how do you show your babies off to your deeply understanding and clearly fascinated spouse, children, friends and visiting Jehovah's Witnesses? Or even remember what’s in your horde?
Don’t let them breathe (or go swimming)
Exposure to air can be problematic for coins. It can accelerate undesirable tarnishing and moisture in the air can cause spotting and even initiate corrosive chemical reactions (like bronze disease) that can ultimately destroy your coins.
The golden mean - not too hot, not too cold, just right
Storing coins in places that have extremes of temperature is also far from ideal and can result in coins deteriorating.
Don’t let your coins take the Electric Kool-Aid Acid Test
Exposure to acidic substances is another way to hurt your coins. Obviously you wouldn't dip your coins in acid (usually that is, there are some cleaning and toning techniques that make use of acids but that's another topic!). But here I am referring to acids and other noxious fumes and vapours which coins may possibly be accidentally or unwittingly exposed to in non archival storage materials like plastics containing pvc or non acid free paper which can damage surfaces and cause buildup of corrosion.
Don't leave incriminating evidence
A storage method that requires or encourages you to handling your coins is probably not a good idea. Your oily and dirty little fingers can permanently disfigure a mint coin with one touch. You will be surprised how easily (and well) a nice shiny coin can show and retain your fingerprint!
What about Ancients?
The vicissitudes time mean that “mint” ancient coins are very rare and usually very valuable. If you have such a coin then you have both my congratulations and envy! I would very much recommend storing it as safely as possible and avoiding the threats outlined above. However, most ancients have come from hordes that have been exposed for hundreds, possibly thousands of years, to the “wrong ways” of storing coins noted above (often to extremes). In most cases coins in hordes are already circulated coins that have been haphazardly thrown together into a container, buried (so exposed to the soil, groundwater (or sand) and perhaps extremes of temperature), eventually dug up again, and then cleaned (sometimes not especially sympathetically) before being made available to collectors. On top of this most ancients weren't perfect to begin with, being hand poured then struck with a hammer and anvil type technique with hand carved dies in order to imprint the design. As such, most of what can be done to a coin has been done to these coins, and their beauty will tend to come to from their uniqueness, which can actually be enhanced by wear and oxidisation (patina). These are coins that wear their history (for better or worse) on their sleeves. It also means that a lot of the concerns above aren't quite as important with ancients as they are with modern coins (indeed some collectors of ancients believed handling improves them!). However, I would still suggest taking all reasonable care.