NGC Conservation: Modern Coins Carrying a Heavy Load

Numismatic Guaranty Company (NGC) uses a variety of proprietary techniques to remove harmful surface contaminants, stabilize and protect a coin's surfaces and, in many cases, improve a coin's eye appeal. After coins are conserved, they are then graded and encapsulated. Below are a few highlights of coins that were conserved and graded by NGC recently.

Ajman ND (1970) 5 Riyals

Coins that are put in long-term storage without being placed in proper containers can develop some serious detail-obscuring residues, which especially occur on the surface of modern issues. This undated (but issued in 1970) Ajman Silver 5 Riyals — a nice coin featuring the international diplomat Dag Hammarskjold — was recently submitted to NGC to remove a profoundly opaque residue that had developed on both sides of the coin. Residues such as these can develop either in the original mint packaging or from poor-quality secondary holders, potentially leading to permanent damage to a coin's surface through corrosion. Luckily, the residue was safely removed from the surface of this coin by NGC's conservationists. After successful residue removal, this coin was able to grade well with NGC.

Ajman ND (1970) 5 Riyals
Before conservation

Ajman ND (1970) 5 Riyals
After conservation

Vatican City 1984 200 Lire

Opaque residues can develop on the surface of any modern coin, regardless of metallic composition. This aluminum-bronze Vatican City 1984 200 Lire was submitted to remove heavy residues hiding the original surface. Modern issues can have particularly sensitive surfaces, so care must be taken in removing the residue safely while avoiding hairline scratches. Following professional conservation, this coin was able to grade very well with NGC.

Vatican City 1984 200 Lire
Before conservation

Vatican City 1984 200 Lire
After conservation

Thailand BE2535 (1992) 10 Baht Commemorative

Long-term storage in original mint holders can lead to the development of feature-hiding residues. This copper nickel Thailand BE2535 (1992) 10 Baht commemorative was recently sent to NGC to address a noticeable hazy residue that had formed, appearing blue in the fields and yellow on the design. Care must be taken when removing residues from fragile Proof coin surfaces. After NGC safely removed the residue, bright reflective fields were revealed. After professional conservation, this coin was able to grade well with NGC.

Thailand BE2535 (1992) 10 Baht Commemorative
Before conservation

Thailand BE2535 (1992) 10 Baht Commemorative
After conservation

For more information about NGC Conservation, visit NGCcoin.com/ngc-conservation.