Remerciez-le!

Remerciez @Admin pour avoir partagé cet document gratuitement, de la manière la plus simple, en partageant sur les réseaux sociaux.

This important guide This important guide is the direct result of Summit 2000,

This important guide This important guide is the direct result of Summit 2000, a precedent-setting conference to examine crucial issues facing dealers and collectors, conducted in December 2000. Organized by the Professional Numismatists Guild (PNG) and the Industry Council for Tangible Assets (ICTA), the summit produced frank and candid discussions to identify numismatic concerns and problems, ways to correct them and proposals to plant seeds for future growth of the hobby and marketplace. Major topics discussed at the summit included numismatic education and grading services. One of the first tangible accomplishments of the conference is this educational booklet for collectors and dealers to clear up misconceptions and misunderstandings about coin cleaning and restoration. Under a committee chaired by Mark Salzberg, this guide is a cooperative effort by (in alphabetical order): Independent Coin Grading Company (ICG); ICTA; Numismatic Guaranty Corporation (NGC); Professional Coin Grading Service (PCGS); and PNG. Numismatics is an enjoyable pursuit. This booklet is designed to help buyers and sellers become knowledgeable about one of the most important and misunderstood numismatic concepts – coin conservation. One of the least understood areas of numismatics centers around the cleaning and conservation of coins. To many collectors and dealers, the word “cleaned” sets off an alarm, since this term is sometimes cited by third-party grading services as the reason for declining to certify a coin. Of course, what the grading services mean when they return an uncertified coin as “cleaned” is that it has been harshly cleaned, leaving a completely unnatural appearance. But when a coin is skillfully cleaned by persons having knowledge of the proper conservation techniques, the result is often a specimen that’s attractive and desirable in the marketplace and that will readily be certified. The widespread confusion that exists over the distinction between undesirable cleaning versus proper conservation has alarmed many coin enthusiasts. It is hoped that this booklet will serve to clarify that distinction and permit both collectors and dealers alike to trade coins in an atmosphere of confidence. The P The Purpose urpose of This Guide of This Guide The cleaning of coins has a long history. When numismatics first flourished, during the Renaissance period of the 15th Century, it was the coinage of the ancient Romans and Greeks that struck the fancy of wealthy gentlemen and scholars. These pieces were typically recovered from hoards buried in antiquity, and it was not unusual to find such coins deeply encrusted with earth and minerals. While the gold and silver coins were fairly easy to clean, due to the durability of their metal, copper and bronze coins presented a greater challenge. Even after removal of soil and other contaminants, these coins frequently retained a fine patina, or coloration. Typical shades were emerald green and Tuscan red, and the owners of these gradually came to prize such patination as a sign of the coin’s antiquity. Even today, collectors of ancient bronze pieces are drawn by their distinctive colors, and detailed descriptions of these coins will usually include the specifics of their coloration. This fact notwithstanding, proper conservation of newly discovered specimens usually includes extensive cleaning to remove encrusted contamination. When coin collecting first achieved widespread popularity in the United States during the 1850s, many budding numismatists obtained their specimens from banks, bullion brokers, toll keepers and others who were likely to encounter large numbers of coins in the normal course of business. As is true of most beginning collectors, their first impulse was to render their coins bright and shiny through harsh cleaning. Many of the surviving United States coins made before about 1840 have been cleaned at some time in an attempt to make them look new, much of this activity having occurred during the latter half of the nineteenth century. This is particularly true of gold and silver pieces, somewhat less so for copper specimens. Introduction Introduction Coins that exhibited normal tarnish were oftentimes dipped into potassium cyanide to strip away their patina and leave them bright. Even the United States Mint’s own curators would periodically spruce up that institution’s collection with a rinsing in cyanide, a risky business given this substance’s highly toxic nature. In fact, the poisonous compound is known to have taken the life of at least one prominent numismatist who, while engrossed in his cleaning endeavors, mistook the deadly chemical for a nearby glass of ginger ale. Fortunately, the use of cyanide to clean coins was abandoned decades ago, and most of the pieces so treated have naturally retoned to some degree. It seems that numismatics is nearly the only field in which the “cleaning” of objects is still perceived as taboo. Collectors are told repeatedly by columnists and other well meaning individuals in the hobby to never clean their coins. This advice is offered as a means of protecting coins solely from clumsy, unskilled attempts at cleaning, but it has left a lingering impression that any kind of restorative work is strictly forbidden. This stands in stark contrast to nearly all other fields of collectibles. For example, the restoration and conservation of art works is performed routinely. Indeed, to not undertake this work is viewed by the art community as negligence. Among conservators of antique furniture, it is not at all unusual for a piece to be completely disassembled, stripped of its varnish and then refinished in its entirety. As long as this work is done with respect to the original materials and to the appearance of the object before it deteriorated, the collecting and museum community view such work as not only natural but quite desirable. Tarnished silverware and pieces of jewelry are not Conservation Conservation is a widely accepted tool is a widely accepted tool condemned as “cleaned” when they have had their beauty restored, so why then are coins? Professional coin conservators are no less skilled and responsible than conservators in other fields, so it is time to re-evaluate the cleaning and conservation of coins in this new light. The term “cleaned” continues to be widely misunderstood. Perhaps, this is because the resulting appearance of a coin that has been cleaned stretches across a broad continuum. There is no obvious dividing line between what is certifiable and what is not, yet a professional grader will intuitively know the difference. This is a challenging concept for the novice collector, and even some experienced hobbyists are uncertain where the boundary lies. When it comes to very old coins, such as United States issues prior to 1840, grading services typically employ a somewhat more liberal standard in determining what degree of cleaning is acceptable. As noted above, many early U.S. coins (and world coins of similar vintage) have been cleaned at one time or another. To condemn all cleaned coins as uncertifiable would render an entire segment of the numismatic market off limits. Some leeway must be given for these early coins, provided that their appearance is still acceptable. Indeed, this raises an important point: The numismatic marketplace usually places cleaned coins into two categories – those that retain an acceptable appearance and those that do not. This is an important distinction, because the major third-party grading services will not certify coins that have an unnatural Where Where W We Stand T e Stand Toda oday y appearance as the result of harsh cleaning. Some of the features that can make a cleaned coin undesirable are hairline scratches from abrasive action, a loss of luster from excessive metal removal and a strange color to the metal (this latter condition is especially true of cleaned copper and bronze coins). In contrast, a coin which has been lightly cleaned in a manner that is consistent with proper conservation techniques will not only remain certifiable but may even become more desirable by virtue of its enhanced appearance. Thus, cleaning is not exclusively a bad thing. It is only the harsh and unskilled cleaning of coins that harms their appearance and makes them unappealing. When it comes to cleaning coins, often one starts out thinking that he or she is an expert. It is only when the sad results are revealed that collectors and dealers learn just how challenging the proper conservation of coins can be. It is a job best left to experts. When is it appropriate to clean a coin, and what techniques should be used? These questions can be answered authoritatively only on a case-by-case basis, yet certain general rules apply. For instance, coins should be cleaned when such action is needed to prevent further deterioration. As an example, a coin that has an active contaminant adhering to it should have this substance removed immediately. Perhaps the most frequently encountered contaminant is polyvinyl chloride (PVC) residue. PVC is a compound added to many plastic coin holders to make them flexible. Such holders are suitable for short-term use, such as displaying a coin for sale, but over a period of years the PVC will leach out of the plastic base and begin to deposit itself on a coin’s surface. This residue appears as a pale