NCS Conservation: Saving Coins from Poor Long-term Storage

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 Company™ (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.

Heavy residues will frequently develop on the surface of coins that have been stored for long periods of time in coin holders open to the environment. This 1937 Great Britain Proof-struck Gold Sovereign had developed a thick detail-obscuring hazy residue on the entire surface. Likely, this residue formed from long-term storage in a coin holder far from airtight. At first glance the residue is so dominant that the mirrored fields are almost completely hidden.

The conservators at NCS have developed techniques to remove such extreme residue from the surface of gold coins without causing any irreversible damage. Following conservation, this Great British gold piece once again exhibits mirrored fields and was able to grade very well with NGC.

Great Britain 1937 Sovereign Before conservation Click images to enlarge.

Great Britain 1937 Sovereign After conservation Click images to enlarge.

Poor long-term storage conditions often lead to the development of many types of surface residues. This silver India ¼ Rupee issued during the British colonial period had developed a distracting line of bright orange residue bisecting the obverse. Careful conservation work was able to remove the red menace while retaining the subtle silver toning color on the remainder of the surface. Following professional conservation, the coin was able to grade well with NGC.

India-British 1911 ¼ Rupee Before conservation Click images to enlarge.

India-British 1911 ¼ Rupee After conservation Click images to enlarge.

Heavy residues can develop on the surface of relatively modern coins as well. This square-shaped commemorative copper-nickel 1966 10 Shilling issued by the Channel Island of Guernsey spent considerable time in lower quality coin holders, allowing an opaque hazy residue to develop evenly across the surface. Once the professional conservators at NCS skillfully removed the residue this issue popular with collectors once again has a reflective lustrous surface. Following conservation this coin was able to grade well with NGC.

Guernsey 1966 10 Shilling Before conservation Click images to enlarge.

Guernsey 1966 10 Shilling After conservation Click images to enlarge.

For more information about NCS, visit NGCcoin.com/NCS.