Conservation of ancient copper coinage

Wyatt Yeager <weyeager [at] comcast__net> presented a very complete
discussion of treating ancient coinage, and finished his posting
with:

>In presenting my methods I am hoping to start a dialogue with others
>that also have worked with conserving metal monies. ...

My attention was drawn to the last section, in which he discussed
storage techniques, but mentioned only the use of dry silica gel in
a "storage container". Silica gel will protect the coins for much
longer if used with an enclosure that has good moisture barrier
properties and is tightly sealed. Far more effective protection from
corrosion would be found using anoxic storage techniques.

Mitsubishi Gas Chemical's RP System and Escal barrier film have a
proven record for archeological metals storage (albeit a demure
one).  A long-term oxygen-free environment is easy to create using
transparent Escal barrier film for an enclosure. Along with the
artefacts to be protected (and mounts/holder, etc.) an appropriate
number of RP System sachets in the enclosure will remove oxygen,
moisture, and corrosive gases.

The Escal film is transparent, so artefacts can be examined while in
the package. No harm is done by opening the enclosures for study,
but to resume the protection of the oxygen-free environment, the
package must be resealed (with new oxygen absorbers when
appropriate).

And an observation: I discovered long ago that this kind of
segregated storage is anathema to collectors of all sorts, who wish
to have their treasures immediately available. This reminds me of
the architects and directors to wish to rid their new galleries of
showcases, glazed frames, and other devices that isolate viewers
from the "museum experience".

Jerry Shiner
Keepsafe Microclimate Systems
416-703 4696
800-683 4696


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                  Conservation DistList Instance 22:54
                 Distributed: Wednesday, March 25, 2009
                       Message Id: cdl-22-54-004
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