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Numismatic Guaranty Corporation
October 2005  
1. The Dangers of PVC Residue
2. Coins of the Month
3. Submitter's Corner



October 27-29
Las Vegas Coin, Stamp, and Collectibles Expo

Mandalay Convention Center
Las Vegas, NV

November 3-5
Palm Beach Coin Show

Palm Beach Convention Center
West Palm Beach, FL

November 16-19
Santa Clara Coin Expo

Santa Clara Convention Center
Santa Clara, CA

December 8-10
Suburban Washington/Baltimore Show

Baltimore Convention Center
Baltimore, MD

The Dangers of PVC Residue

One of the most common and destructive residues encountered on a coin is the plasticizer PVC. The chemical, PVC, makes plastic softer and more pliable and is frequently added to the make up of popular coin holders such as flips. The problem with PVC is that under certain environmental conditions and through the effects of time, the plasticizer will come out of the plastic and collect on the surface of the coin inside the PVC-laden holder. If this residue is allowed to sit on the surface and fester long enough, it will eat into the surface of the coin resulting in a certain type of environmental damage known as PVC etching. Even for new coins, PVC residue can be bad news.

To combat the ill-effects of PVC, both NCS and NGC recommend submitting your coins in what is referred to as “hard” flips. Hard flips are those that have not been treated with the plasticizer PVC and have a harder more brittle texture than do the “soft” flips that have PVC added to their make up. Flips are intended as a short-term storage option. When selecting a flip for short-term storage, such as those used to submit your coins for professional conservation and grading, choose those with a stiff feel that are free of dangerous plasticizer residues. Even very short periods of storage, such as the time for a package to be delivered through registered mail, can have a negative impact.

A recent submission of modern commemorative coins came to the attention of NCS and points out a problem seen too often. All of the coins had been shipped in the PVC-laden “soft” flips. In a short time, these coins had developed the first stage of PVC contamination. All the coins—the recent 2005 Marine Corps issues—had acquired a hazy residue hiding the fields. This residue presents a problem for both the coin’s long-term stability and its ability to grade. With such a hazy PVC residue, the coin would not be able to grade as high as it would otherwise. Removal of the PVC residue allowed the coin to realize its true potential.

This 1924 S 5c is a prime example of the irreversible damage that can happen when a PVC residue is left on a coin’s surface. As PVC contamination advances, the haze on the coin’s surface becomes thicker and green in color. The thick green oily residue is the most destructive PVC contamination. The reverse of this coin was grossly affected by a PVC residue that, once removed, left visible pits all over the surface of the coin.

Even the newest and freshest coins can be adversely affected by PVC. A PVC haze can prevent a coin from grading out as much as it could in the short-term and if left to become more severe could cause irreversible damage to a coin’s surface. For information on how to submit coins with PVC residues for professional conservation, contact NCS Customer Service at 866-627-2646 or "".

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Coins of the Month
Conservation 5024124-002

Popular with both collectors and non-collectors alike, the Indian gold design is unusual with its devices sunk below the fields. Unattractive spotting was plaguing this example of a 1911 $2.50 gold coin. Removal of both residues and what is commonly referred to as “copper spots” with professional conservation left this coin with a natural appearance enhancing the beauty of this unusual design.

Coin of the month before
Coin of the month after

Encapsulation: 5042477-006

EncapsulatedThe Clark-Gruber Pike’s Peak Gold issues dated 1860 and 1861 are distinctive in the popular U.S. Territorial Gold series for their unique design. The triangular mountain on the obverse bears no resemblance to the actual mountain it is identified as being. As with many of the territorial issues, counterfeit examples do unfortunately exist. It is important to certify a piece as genuine even if it does have a problem that will prevent it from encapsulation by NGC such as this example’s improper cleaning.

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Submitter's Corner
The NCS Submission Form

If you have any special concerns regarding either the conservation or encapsulation of coins you are submitting, feel free to include notes attached to either the holders or written in the margins of the submission form.  NCS customer service will be sure that your concerns are considered at the appropriate point in the processing of your submission.  However, remember that NCS reserves the right to make the final decision on the conservation of coins. 

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