Fingerprints And Conservation
Posted by F. Michael Fazzari, Senior Conservator on 11/8/2002
There is a correct way to handle your coins for a reason. Our hands contain body oils, which can be acidic. There are also a variety of other elements that we have come in contact with, that when transferred to the coin by improper handling can cause permanent damage to a coin's surface.
There is a correct way to handle your coins for a reason.
Our hands contain body oils, which can be acidic. There
are also a variety of other elements that we have come
in contact with, that when transferred to the coin by
improper handling can cause permanent damage to a coin's
surface. It is amazing how many coins we see at the
NCS with fingerprints. They not only make the coin unsightly,
but also may permanently etch its surface if left untreated.
The best way to deal with fingerprints is to avoid putting
them on your coins but accidents do occur.
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If caught when they are fresh, fingerprints can be removed
from a coin's surface. When removing fingerprints from
a coin, use the mildest treatment possible. This will
keep the coin in its most natural state of preservation
and reduce the chances of damaging the coin's original
surfaces or natural color. There is a big difference
between submerging a coin in a solution and rubbing
its surface with an abrasive chemical. There is a possibility
to leave hairlines on its surface if some dislodged
grit is pushed around with the chemicals.
As a fingerprint's residues mature, they will "set"
on the coin. In these cases, a mild acidic dip may be
needed to remove it. If caught in time, and done by
professionally, there will be no trace of the print
remaining and the coin can be returned to its original
appearance. It is also extremely important to properly
neutralize the coin to lessen the chances of problems
developing in the future. In spite of what you may have
read before, a few submersions in a very mild acidic
solution may have no visible effect on a coin's originality
if they are performed properly and neutralized immediately.
However, do not attempt this on copper coins.
If fingerprint residues are allowed to remain on a coin,
they may actually etch the surface. Once this has occurred,
it is virtually impossible to remove it without abrasive
cleaning or stronger acids, which will almost certainly
damage the coin. The etched surface cannot be restored
and will be dull and lifeless. In these cases, the cleaning
can be easily detected.
When in doubt about the removal of any contaminant for
foreign material from a coin, consult a professional.
The damage that can result from improper
cleaning is almost always irreversible.