What do you do when your collection suffers water or moisture damage? This is a serious problem for collectors who were unfortunate enough to be in the path of the two devastating hurricanes that made landfall recently in the region of Louisiana and Texas, but it is a problem for all of us as well.
Triage is an immediate requirement. Try to salvage the valuable stuff first. Ignore the low-value stuff and recognize that paper and cardboard packaging material can never be restored.
Remember also that coins and paper-related numismatic items (paper money, souvenir cards, etc.) that have suffered water or moisture damage can never be quite fully restored to their original state. They may, however, be salvageable to a point where only a professional can tell something was done, depending on the amount of damage, the extent to which the collector is willing to go to restore the damaged items, and the extent to which the collector is willing to absorb costs relating to restoration.
The former value of the collectibles is paramount, as is the potential value of the items if restored versus if they are not restored. Coins and paper money of low value are likely not worth considering for restoration, whereas a coin or paper numismatic item of some significant value may be worth rescuing.
If you have a complete collection of Lincoln cents that is now waterlogged following a recent hurricane your concentration should logically focus on the key date coins. Those 1909-S, 1909-S VDB, 1914-D, and 1922 No “D” cents are going to be a lot more costly to replace than are the common dates that complete the set. Common sense should tell you that the 1909-S VDB should be assessed for damage and restoration first.
If any of the key coins have been graded by third-party services, contacting the service is a good place to start. Ask their advice regarding at the very least having them re-examine the coins and their encapsulations. In some situations the coins may be fine. In other cases it may be safer to have the coins reslabbed. Let the professionals make this decision. They know what they are looking for. You don’t want your Mint State 65 Red 1909-S VDB Lincoln cent to turn brown and perhaps become spotty at some later date.
Professional restoration may be the logical option at this point. Cleaning is a dangerous task, especially when it is done by persons who do not know how to do it properly. More value can be lost than restored by an improper cleaning.
If you are like most collectors, most or all of your coins are in their raw unslabbed state. That means you might feel you are pretty much on your own.
Whereas under normal circumstances cleaning is a no-no, it may become the only option following a disaster, but remember that this is not a riskless task. If you are inexperienced and unsure, but still determined to go ahead and try cleaning, perhaps reverse triage should be your goal. Experiment first on the low value coins to see how you do. You may at that point then reconsider your decision not to pay professionals to do it for you.
If your collection appears to have been exposed to water or to excessive moisture, the first thing that must be considered is the composition of the damaged collection. Do you have gold, silver, or base metal composition coins? Do you have paper money? Do you have proof and mint sets, or something else in which the paper composition original packaging is important to the value of the collectible itself? Was your collection housed in a paper-composition coin album?
Each of these four substances requires a different form of restoration, assuming the collectible will be subjected to restoration.
Gold is amazing. It is treasured for its colorful beauty, but it is also prized because of its durability. You can bury it in the ground and dig it up at a much later date only to find it has survived unscathed by the foreign elements around it. It is a noble metal, that is, it is unlikely to discolor.
Regarding collector gold coins that have been subjected to water or excessive moisture the greatest problem may be with foreign objects such as dirt and debris that have now made contact with the coins. This will likely be the case when there has been flooding or a hurricane. The only damage the gold coins may experience will be from the contact with such foreign materials, not from corrosion resulting from contact with water or moisture.
Such contact may have left the coin surfaces dirty, or in some situations may have left marks on the surfaces due to the natural malleability property of gold.
A delicate bath mix of non-abrasive liquid detergent and warm water may be all the treatment a formerly submerged gold coin may need. Any scrubbing should be avoided at all costs since this will likely leave hairlines (scratches) on the coinage surfaces. Judicious brushing may be necessary to remove grit, but remember that gold is soft. Any contact with a brush or friction caused by the elimination of foreign particles may result in hairline scratches.
Silver is a different problem. Water- damaged silver coins are well known to coin collectors since many of them have been salvaged from shipwrecks over the centuries. Unfortunately, unlike gold, silver will react with water with which it comes into contact. This may be household moisture, moisture from having been buried, water contact from submergence, or even from a hurricane.
Silver tarnishes even when left alone. Some collectors like toned coins while others prefer them white. Nobody prefers them with indications of water damage. Once again, liquid soap and warm water may be all that is required to restore a coin that has literally gone through a hurricane. If this appears to be true, be careful not to use any abrasive detergent or a cloth. Once again, hairlines may otherwise appear. Water spots are another potential problem when coins are not patted dry but are wiped dry with a cloth.
Unlike with gold, when silver needs to be cleaned there will be evidence of the cleaning no matter how careful the collector may be. Silver coins will look artificially bright and silvery regardless of how little the toning and original mint luster have been disturbed.
The worst problem regarding water or moisture damage appears on copper and bronze coinage. Silver, like gold, has noble properties. When moisture and soil mix with copper or bronze an electrolyte that conducts electricity resulting in what is called electrolytic corrosion is caused by soluble salts in the soil that have been dissolved. This natural electric cell saves gold and silver by corroding the less noble metal – typically being copper if we are talking about a coin. Since the copper is alloyed with other metals that may have better noble properties this corrosion will impact those metals and the total coin as a result.
When copper composition or alloy coins are subjected to moisture or water, such as from the waters accompanying a hurricane, distilled water or pure olive oil and a soft bristle toothbrush may be the best tools. Mechanical methods of cleaning coins showing signs of water damage will likely leave scratches. Dirt and clay can be removed using distilled water or olive oil, while removing the harmful soluble salts at the same time.
Olive oil is popular for cleaning ancient coins once these coins have been unearthed. Olive oil is reliable, but it takes a significant amount of time (several months) to soak a coin in the oil effectively. The only way to speed up the process is to heat the oil. This must be done carefully, using a thermostatically controlled cabinet. Olive oil should not be heated above a handleable temperature. Olive oil is flammable. For this reason, gas burners and electric hotplates should be avoided as heating sources. Use a closed container and change the oil on a monthly basis.
If water is your weapon of choice, remember it needs to be distilled water, since tap water contains significantly more minerals. These minerals may create unsightly spots on the surfaces of a coin you are trying to rescue. When drying a coin first cleaned with distilled water, either air dry it or pat it dry. Do not rub the coin – it will leave marks.
Water damage to such numismatic paper products as bank notes, coin albums and the official packaging in which modern collector coins may come is the other problem. Although the thrust of this article is towards what to do with a collection that just went through a hurricane, water damage can also come from burst water pipes or even from improper exposure to air conditioning.
Not only the composition, but the age and condition of the paper determines the rate at which it will absorb water. Paper manufactured after 1840 typically absorbs moisture up to an average of 60 percent of that paper’s weight.
Coins in government packaging, such as proof and mint sets, need to be carefully removed from their packaging and individually restored as has been suggested above. The packaging itself may be too damaged to salvage. Where possible, restore the packaging just as you would any other paper product reviewed in this article. The most unfortunate thing about the damaged packaging is that collectors are purists – they like to have all the packaging original and undamaged. Coins and other numismatic collectibles that are no longer in their original packaging, or are in damaged packaging, command lower prices than do like items that are not damaged.
Once a hurricane or other environmental problem has done its damage to your numismatic paper products, your first priority becomes stabilizing the damaged items. Pockets of stagnant moist air must be avoided. Expect mold to appear within 48 hours of the water-related damage. Although freeze or vacuum drying are options, most likely air drying will be the method used to recover water damaged numismatic items.
When air drying something airflow, not a higher temperature, becomes important. A dehumidifier or fan may speed up the drying process while a fungicide may prevent mold.
Pressing bank notes, coin albums and the like may remove water more quickly, but it will cause paper to stick to other paper it has contact with. Since water damage to bank notes is particularly serious, prioritize which notes to dry first in case not all can be saved. Where possible, place the wet paper products in a constant 18.3-degree Celsius, 50-percent humidity environment.
Since the objective is to lower the humidity of where you have your water damaged notes, albums, or coin packaging stored remove the wettest items from that area where possible.
Water damage unfortunately is permanent. Once a numismatic item has been in contact with water or excessive moisture due to a hurricane, flood, or other disaster, its value and quality will be impacted. By being aware of what can be done to reclaim what has been damaged, your collection may not sustain as much damage as might occur if no action is taken at all.
The lesson for those of us who did not suffer hurricane damage is to take preventive measures. Is your collection stored in an environment safe from fire, floods, storms and other threats? Is it properly insured? Think about these questions now and you will that much further ahead should you ever experience the unthinkable as collectors in the Gulf region have.