Coin Collecting - How To Clean Your Coins
Though debates rage about whether and how to clean your coins, most serious collectors agree on some basic guidelines.
The first principle of cleaning coins is similar to the Hippocratic Oath for physicians: Do no harm!
With your collectible coins, you must also avoid damage at all costs. Most coins have already experienced wear and
degradation of various kinds. Exposure to air, banging together in
carrying bags, use in commerce and a host of other actions will result
in nicks, scratches and corrosion.
Don't make the situation worse once you acquire the coin for collecting or trade.
That principle implies a method for deciding when to clean a coin.
If leaving the coin untouched will result in further degradation - because
of the presence of corrosive chemicals, dirt or other material - then
clean the coin GENTLY.
The goal is never to make a collectible coin look 'shiny and new', but merely to
prevent any further corrosion or damage from chemicals the coins may
have come in contact with. The green stain on copper coins is a common
example. This is copper oxide - in essence a kind of rust.
What you use to clean your collectible coins with will depend on the kind of
material you are trying to remove. But there are some common household
ingredients that can be used safely.
Be sure to wash your hands and lay out a clean working area first. Test
any method you use on an ordinary coin before using it on a collectible.
Ordinary liquid dishwashing detergent is useful for removing surface
dirt. If soaking doesn't work, apply a small amount to the surface and
rub very gently with the thumb and forefinger. Do one coin at a time
and keep them separate so they don't scratch or ding one another.
Lemon juice contains a weak acid that is useful for removing oily
smudges, including those produced from unwashed hands. Sometimes a
short soak will remove material without the need for rubbing. Try that
first. Keep in mind however that removing oil exposes the surface to
air. The oil serves as a protective coat. That can lead to oxidation.
Coins should preferably be air dried, but if you must rub use an
extremely soft cotton cloth and rub very gently. Another method is to use cloths made especially for cleaning eyeglasses, as
they are non-abrasive. However, you can also find specially designed cloths for cleaning coins.
Before using any kind of tarnish or stain remover, similar to the sort
commonly used on silver spoons, for example, consult a coin dealer. You
may actually lower the value of the coin by making it less tarnished.
Always use the type especially made for coins.
Dealers and serious coin collectors will in rare cases use electrolysis
to clean certain coins. Though, again, most coins are never cleaned or
polished at all. Home kits exist or can be made for this purpose, but
they should be used with extreme care.
To repeat: you may accidentally decrease the value of your collectible coin simplhy by trying to 'improve' it. When in doubt, consult a dealer before cleaning any coin.