Have you ever wondered what a coin collection might look like after it is pulled out of a house fire? The following is from the Numismatic Conservation Services (NCS) newsletter and shows the remarkable conservation of a cherished collection after a damaging fire.

“A house fire can be especially devastating to a prized coin collection. A once pristine, cherished collection can turn into a horrible blackened mass. However, with some careful conservation work, all is not lost.

The first stage in conserving a group of coins such as these pictured is to safely remove them from what remains of their holders. Removing coins entombed in deformed coin holders is a challenge. The standard methods of removing coins from third-party grading services’ holders are usually not an option. To make the task even more difficult, every coin and every holder is different. The heat of a house fire can melt the plastic that makes up the majority of quality coin holders. While still in the fire, this plastic, in the molten state, will combine with soot and other materials. After it has solidified, the conservator’s job is more difficult.

Once freed from the burnt plastic mass, the next step is to remove the small bits of adhered plastic from the surface of each of the coins as safely as possible. Different plastics react to conservation efforts in wildly different ways. Materials from the fire itself also adhere to the coins and have to be removed without damaging the surface of the coin. Coins can sometimes be left with lightly stained surfaces, often a result of the heat of the fire.

A pattern emerges as the collection is conserved. Coins in the best holders, those certified by third-party grading services such as NGC, are the best off. Coins housed in coin tubes and individual holders are often damaged by the action of the fire or necessary actions taken in the aftermath.

The conservation results on this group of coins can be described as better than expected. The classic gold coins came out especially well as did the Morgan and Peace Dollars. This collection was submitted to NCS by Liquid Bullion Coin & Collectibles of Houston, Texas. “Wow! NCS was a life saver for our client. He was afraid he had lost everything and came out with over $27,500 in Rare coins, Bullion, and Generic Gold,” commented Danny Lee, Liquid Bullion’s CEO.”

By Numismatic Conservation Services, LLC (NCS)

The term “carbon spots” refers to tiny black concentrations of corrosion. Oftentimes these are so small as to escape notice by the naked eye, though they may be seen with low-power magnification. Also called “flyspecks” by some in the hobby, these spots are actually slightly raised from the surface of the coin, as the corrosion forms around some particle of organic matter, such as paper dust (often present with coin albums and cardboard “2×2″ stapled holders) or human saliva deposited unknowingly by a numismatist during casual handling. Oxygen, humidity, and other atmospheric elements react with the debris to form a minute mound of corrosion around it, and this is called a carbon spot.

Removal of the debris will usually stop the reaction, and thus worsening of the spot, then and there. This may be as simple as removing the offending particle. The resulting corrosion, however, will remain as an unsightly black speck that can range greatly in size from nearly microscopic to as much as a quarter-inch in diameter, depending on how much mass the contaminant possessed and how long the reaction was occurring.

Most often carbon spots will form on the surface of copper or bronze coins. The highly reactive nature of copper as a metal will often lead to their formation, but US copper-nickel coins as well as other copper-nickel coins from around the world are also quite susceptible. Most nickel alloys used for United States coinage are a combination of 75% copper and only 25% nickel. This includes the three- and five-cent pieces made since 1865 and the outer layers of our current dimes, quarters and halves, as well as those of the dollars coined 1971–99. The thick cents dated 1856–64 included 88% copper to only 12% nickel and, given their greater copper content, have an even greater susceptibility to developing carbon spots.

For copper-nickel coins displaying carbon spots, proper conservation can remove both the contaminants and the resulting spots. In some instances a pale ghost of the spot may remain, and removal of carbon spots will usually leave tiny bald patches in a coin’s toning. For these reasons, copper-nickel coins that undergo removal of carbon spots will typically have their toning removed as well during the conservation process. This is preferable to having such eye-catching gaps and is in the best interest of the coin’s long-term preservation.

You’re at a coin show or a dealer’s shop when you ask to see a coin that’s in a flip, one of those double-pocket, plastic envelopes that so many dealers use to display uncertified coins. When he or she hands you the flip, it seems that the coin is actually stuck to the inside of it.

Some flexing of the soft flip is enough to make the coin break free, and then you see it—that pale green outline of the coin imprinted on the inside of the flip. You, my friend, have experienced a PVC moment.

PVC is short for polyvinyl chloride, a popular and widely used plastic that has countless industrial applications. In most of these applications PVC’s qualities are completely benign. In fact, using this plastic for coin flips is OK, too. Where the problem lies is that such storage is suitable only for the short term, say, less than six months. After that time the chemical softening agent that gives PVC its great flexibility may start to leach out. Over time, this can settle onto a coin and deposit an oily film—that sickly, green slime that leaves an outline of the coin on the flip and adheres to the high points of the coin itself.

Prolonged exposure to PVC deposits in the presence of moisture can actually lead to the formation of hydrochloric acid which permanently scars the coin. In its earlier stages, however, PVC film is removable with proper conservation. Any coin displaying such green, oily film on its surfaces may be submitted to Numismatic Conservation Services, LLC (NCS) for removal of the contaminant.

Using PVC coin holders is perfectly all right for short term storage and display. If a coin hasn’t sold after a few months, the dealer should place it in a fresh flip, but this doesn’t always happen. Collectors should never use PVC products for long term storage, a fact which became abundantly clear when a particular brand of coin album had to replace this plastic in its product line with another, less harmful one about 20 years ago. The damage to the products’ reputation, however, was irreversible, and the company went out of business. Old-time collections still come onto the market in such albums, and they’re not a pretty sight. (more…)