{"id":1435,"date":"2017-12-20T09:25:45","date_gmt":"2017-12-20T09:25:45","guid":{"rendered":"https:\/\/www.mintageworld.com\/blog\/?p=1435"},"modified":"2017-12-20T09:30:27","modified_gmt":"2017-12-20T09:30:27","slug":"coin-cleaning-tips-experts","status":"publish","type":"post","link":"https:\/\/www.mintageworld.com\/blog\/coin-cleaning-tips-experts\/","title":{"rendered":"Coin Cleaning Tips from Experts"},"content":{"rendered":"

The world is a dangerous place for valuable coins. Hazards lurk in the air, in storage containers, and even on collector\u2019s fingertips. Exposure to these hazards can subject a rare coin to irreparable damage that can greatly diminish its value. Fortunately, there are ways to guard against such risks and maintain these coins in their original and pristine condition using different coin cleaning methods. There are also ways of protecting coin investments by storing them properly. All these prudent steps can make the world a much safer place for rare coins.<\/p>\n

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\u201cCleaning\u201d is a term with positive connotations, but in some cases, it can be extremely negative when applied to coins. Unknowledgeable individuals, in an effort to improve their coin\u2019s appearance often end up causing devastating damage to their collectability and resale value. When performed by skilled professionals, however, certain types of cleaning can actually retard some destructive processes and enhance a coin\u2019s appearance.<\/p>\n

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Some mild types of coin cleaning under some circumstances might improve a coin\u2019s appearance while other types could destroy its premium value. All coin cleaning has to be done with care; coins are delicate and susceptible to damage if mishandled. It is advisable to leave coins cleaning of any kind to experts.<\/p>\n

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There are two types of coin cleaning: abrasive and nonabrasive<\/p>\n

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Abrasive Coin Cleaning<\/h3>\n

This is the most harmful type of coin cleaning. A coin\u2019s grade is based primarily on how much wear it has if it\u2019s a circulated coin and how well it has been preserved in its uncirculated state. Abrasive cleaning removes a part of coins and thus lowers the grade. Furthermore, abrasive cleaning activates metal\u2019s oxidation process. Even if a coin is shining brightly one day, the next day it could turn black from having had its metal activated.<\/p>\n

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Abrasive cleaning removes the top layer of metal of a coin. Using this method is like subjecting a coin to circulation! From the friction or rubbing on the coin\u2019s surface from cleaning, part of the coin\u2019s design is worn away.<\/p>\n

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Any process is abrasive that requires an individual to use a wire brush to clean coins. Also, any process that involves treating coins with acid is abrasive. The same effect can be achieved chemically that a wire brush achieves. One should never clean any coins abrasively. Coins discovered at sea as part of an underwater exploration are sometimes cleaned abrasively so that they can be identified. This is the only acceptable numismatic use for abrasive coin cleaning<\/em>.<\/p>\n

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Mildly Abrasive Coin Cleaning<\/h3>\n

Acidic Dips<\/h3>\n

Some coin cleaners \u2013 for example, those designed to remove light tarnish \u2013 are mildly abrasive. Acid-type solutions used for \u2018dipping\u2019 are often abrasive. These \u2018dips\u2019 are controversial because they are used so often. Acid tends to leave the surface of a metal looking pitted, not scratched, as physical abrading does. A split-second dipping might not be very harmful, but immersing a coin for more than a couple of seconds could be. It is advisable not to dip any valuable coins until one has mastered the technique of dipping. Many century-old coins have been dipped. It just isn\u2019t possible for 100-year old silver coins to be as brilliant as they were in their original mint state. Toning is a natural part of a coin\u2019s aging process.<\/p>\n

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Each coin has many little flow lines which can be seen most clearly under a scanning electron microscope. These flow lines result from the minting process and the depth. The quality of these lines produces a coin\u2019s gleam. If these little lines are flattened or eliminated, a coin loses luster. It\u2019s like flattening the waves on an ocean; the ocean wouldn\u2019t reflect light at every angle from which one has viewed it.<\/p>\n

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Abrasive cleaning removes these flow lines while mildly abrasive cleaning reduces their intensity. Dipping is cumulative; coins lose another tiny layer from each dipping. Further, some coins have no high-quality flow lines, to begin with. If these coins are dipped, their grade will be lowered substantially. Over-dipped coins are lackluster and very unattractive. The appearance of some coins can be improved by dipping, but one has to know coin surfaces very well to know which coins can be dipped and which will lose luster.<\/p>\n

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\"Coin<\/a><\/p>\n

Hairlines<\/h3>\n

Hairlines are patches of parallel striations that interrupt a coin\u2019s reflective properties. Hairlines do not appear on Proof coins exclusively, but their presence is most detracting on Proof coins because these are supposed to have fully reflective surfaces. Hairlines are often caused by light cleaning, such as those done with facial tissue to remove fingerprint.<\/p>\n

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Many people often confuse hairlines with die-polishing marks, which are also patches of parallel striations. The difference is that these resulted from the polishing of the die, not of the coins. Die-polishing marks are raised, whereas hairlines are indented.<\/p>\n

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Nonabrasive Cleaning<\/h3>\n

Nonabrasive coin cleaning does not adversely affect a coin\u2019s top layer of metal and, on sense, does not \u2018eat into\u2019 the coin to achieve its effect. Submersing a coin in water, for example, is a nonabrasive cleaning method. Nonabrasive cleaning methods are used to help preserve coins, for they remove particles and other chemicals from the surface that might later negatively affect the coins. For example, if an individual accidentally sneezes on a coin, one should use a nonabrasive method of removing saliva. Saliva later tones the surface a dense, dark color.<\/p>\n

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\"coin<\/a>Nonabrasive cleaning methods are being recommended increasingly before long-term storage. One chemical in particular, trichlorofluroethane, was used for years as degreasing solvent and prized for not leaving a residue on the coin\u2019s surface. This chemical is banned as it is an ozone-destructive solvent. Preservation experts recommend the use of denatured alcohol in its place.<\/p>\n

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Coins are essentially dirty. During their manufacture, their metal is rolled, punched, annealed, die-struck, and handled by various mechanical devices. Even the most well-preserved coins are beset by various contaminants: oil and grease, rag dust, bag dust, metallic particles and others.<\/p>\n

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\"coin<\/a><\/p>\n

After the coins leave the mint, they are further contaminated by counting machines and handling. When a person holds a coin, they contaminate it too. A dandruff fleck, a drop of saliva, and the oil from one\u2019s finger have the potential to significantly lower a coin\u2019s level of preservation. The rate of a coin\u2019s deterioration depends a lot on the metal of which it\u2019s made, the atmosphere, the contaminants on the coin\u2019s surface, and the handling of the coin.<\/p>\n

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Normal pollutants found in the air can cause problems by combining with oxygen to damage a coin\u2019s surface. Gases produced while a coin is housed in a plastic holder can also be a cause of damage. Caustic chemicals, such as compounds containing sulfur, can harm coins too.<\/p>\n

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If one decides to neutralize or solvent-clean a coin, they should be certain that the coin\u2019s surfaces are pristine and haven\u2019t been tampered with. The surfaces must be free from any kind of coating for the solvent cleaning to be successful. It must be stressed upon to never use anything sharp or harsh (even cotton swabs) during solvent cleaning.<\/p>\n

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How to Clean Coins Nonabrasively?<\/h3>\n

Even the most harmless products can be misused, and even good products used incorrectly might have a negative impact on some coins. The best way to test the impact of a coin-bathing solution is by applying a small amount to the coin\u2019s edge and observing the result. Since the rim is made from the same material and dies as the rest of the coin, an individual will know not to use a certain bathing solution if it reacts negatively with the edge. However, this still is not a complete assurance that the coin product tested will not harm the coin.<\/p>\n

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Preservation Precautions<\/h3>\n