Conservation Showcase: 1981 China 2 Jiao
Posted on 4/10/2012
A recent example from our conservation laboratory.
Green is the preferred color on the cash in our wallets but green on the surface of a coin is often the indication of a sinister process at work. A green haze or deposit is most often a sign that PVC, a chemical found in many inexpensive poor quality coin holders, has begun to deposit on the surface of a coin. This PVC residue can over time begin to corrode or etch permanently into the surface of a coin. Removal of any PVC residue once it has started is imperative.
This 1981 2 Jiao issued by the People’s Republic of China had spent many years in a PVC laden holder. The green PVC residue had become so extensive that one might question whether or not this is made of brass. PVC residue as advanced as this requires careful conservation to remove the offending deposits without doing damage to the surface beneath in the process. Our conservation efforts were successful and this coin was able to grade at NGC with standard numeric grading.
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