NCS Conservation: Residue Removal Helps Three Modern Coins Shine

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.

Gold coins are in general the most impervious to corrosion but even modern gold coins can develop some unsightly residues and blemishes due to improper long-term storage. This Fiji 1975 gold $100 commemorative coin had developed several large copper spots and an unsightly black residue along the rims on both sides. Red copper spots are a common occurrence on both modern and vintage gold coins.

The professional conservators at NCS have developed techniques to safely remove the red copper spot as well as any unpleasant residue and toning from the surface of a modern coin without damaging the original surface underneath. Luckily for this substantial gold coin it was able to grade exceedingly well following professional conservation.

Fiji 1975 $100 Gold Commemorative Before conservation Click images to enlarge.

Fiji 1975 $100 Gold Commemorative After conservation Click images to enlarge.

Quite often the culprit in the development of unsightly and potentially damaging residues is the original mint packaging. It was likely long-term storage in a holder open to the environment that led to a heavy dulling residue to develop on the surface of this France 2015 10 Euro silver commemorative issued to celebrate the publication of the world-wide popular Little Prince story. Careful conservation must be performed to remove the offending residues without scratching the fragile mirrored surfaces of this proof coin. After successful conservation, this coin was able to grade very well with NGC.

France 2015 10 Euro Proof Silver Commemorative Before conservation Click images to enlarge.

France 2015 10 Euro Proof Silver Commemorative After conservation Click images to enlarge.

A poor choice in coin holder can lead to unattractive and dangerous residues. This Mint Error 2001-P North Carolina state Quarter was recently submitted for NCS conservation to address a opaque sticky residue that evenly covered the entirety of this broadstruck error coin. Opaque residues such as this often form from extended use of inferior coin holders containing PVC and with time can begin to corrode the surface of a coin held within. Luckily, NCS conservators have developed techniques to safely remove these kinds of sticky residues without damaging the surface underneath. Following professional conservation, this modern mint error coin was able to grade well with NGC.

2001-P North Carolina State Quarter Mint Error Before conservation Click images to enlarge.

2001-P North Carolina State Quarter Mint Error After conservation Click images to enlarge.

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