Conservation Showcase: Proof 1880 5 Cent
Posted on 3/29/2010
A recent example from our conversation laboratory.
The mere mention of PVC residue can sound off alarm bells in the numismatic community. This chemical is added to make inexpensive coin holders more pliable but it can lead to serious problems for the coins housed for long periods of time in them. A green haze to thick green deposits can be the first signs of PVC residue contamination. If left to their own devices, PVC residues can corrode and damage the surface of a coin.
This 1880 Proof Nickel was submitted to NCS for the removal of early stage PVC residue. The green haze of PVC residue can be seen fairly evenly across the fields of this coin. Several small spots of corrosion can also be seen on this coin particularly on the obverse at around 4 o’clock likely caused by prolonged contact with moisture at those single points on the coin. The conservators at NCS were able to remove the PVC residues and take measures to both reduce the appearance and future development of corrosion. With the PVC residue, the coin would not qualify for certification with NGC but following professional conservation with NCS, this proof shield nickel was able to grade numerically with NGC.
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