NCS Conservation: PVC Residue Safely Removed
Posted on 9/14/2021
Numismatic Conservation Services™ (NCS®) uses a variety of proprietary techniques to remove harmful contaminants, stabilize and protect a coin's surfaces and, in many cases, improve a coin's eye appeal. After coins are conserved by NCS, they are seamlessly transferred to Numismatic Guaranty Corporation® (NGC®), an independent affiliate of NCS, for grading and encapsulation.
Below are a few highlights of coins that were recently conserved by NCS and graded by NGC.
Long-term storage in soft flips containing PVC will lead to some unattractive and corrosive residues forming. This 1922-S Peace Silver Dollar was recently submitted for NCS conservation to improve its appearance by removing a thick jade green residue that had formed in stripes on both sides of the coin.
Heavy residues such as these can be troublesome to remove but professional conservators at NCS have developed techniques to remove these residues without damaging the coin underneath. After successful PVC residue removal, this coin was revealed to be bright and lustrous and subsequently able to grade numerically with NGC.
A green color is often a clear indication of PVC residues. This silver 1966 Norway 5 Kronor was submitted to remove a uniform thick opaque residue obscuring the surfaces. While not green, this type of residue is likely due to long-term storage in PVC laden holders. Following professional conservation to remove the obscuring residue, this Norwegian silver coin was able to grade well with NGC.
Modern coins often develop unattractive residues through poor storage. This copper-nickel 1975 South Korea 100 Won coin was recently sent to NCS to address a heavy PVC residue that had developed uniformly over the entire surface. Even Mint State strike circulation issue coins can develop PVC residue after years of storage in soft flips containing PVC. Luckily for this popular South Korean coin, the PVC had not irreversibly damaged the surface metal, and following professional conservation, this coin was able to grade well with NGC.
For more information about NCS, visit NGCcoin.com/NCS.
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