Conservation Showcase: 1939-S Oregon 50 Cent
Posted on 9/13/2011
A recent example from our conservation laboratory.
Long-term storage in a coin holder containing the plasticizer PVC can have a visible effect on the coin inside. A green sticky residue had formed fairly uniformly over the surface of this otherwise white coin. The PVC chemical is an additive to help soften the plastic used in mostly so-called soft flips. The harder and more brittle hard flip version does not contain the PVC plasticizer. A coin with PVC residue will not be certified if it is sent directly to NGC for grading but it can often be removed through professional conservation.
This 1939-S Oregon Half Dollar was bright and white aside from the terrible green residue concentrated around letters and in low points of the design. The conservators at NCS were able to remove the destructive PVC residue from the surface of this coin revealing a white silver coin relatively free from damage. This coin was able to grade at NGC with standard numeric grading.
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