For over 150 years, coin collecting has been a popular hobby in the United States, with a dedicated group of enthusiasts numbering in the millions. The very nature of coin collecting places a great emphasis on the value of the coin, a lot of which has to do with its current condition.
In terms of valuing, the coins whose surfaces are close to their original appearance, as well as natural toning, tend to net more value than coins that have been chemically altered, including treating with acids, such as the dipping process. Treating a coin with chemicals damages the layers to the surface of the coin, and can be irreversible. Once a coin has been treated, its original state can not truly be restored. This applies mainly to the older, rare coins, as coins that are newly minted gave little to no toning.
Dipping the coin causes its appearance to be brighter, which is a result of the stripping of its layers, altering the characteristics of its flow lines. While the coin may appear to be brighter, it is important to understand that the process involves removing metal from the coin. Because the process of dipping changes the coin’s texture, the toning of the coin will vary from what it would have been had the process never occurred.
Different coins throughout history have been minted with different finishes, ranging from subtle to obvious. The change in texture resulting from dipping a coin can take away from the coin’s appearance, and can affect their pedigree markers. Pedigrees add to a coin’s value, and must be recognizable and traceable in order to be identified. In addition, they establish a chain of ownership that is part of the coin’s history, which is an important factor in coin collecting. Changing the coin’s appearance over time can not only affect its pedigree, but have a significant affect on its value. The results of modifying the appearances of coins is not always immediately apparent. It can sometimes take weeks, or even months and years to see the effects.
Modifying the appearance of a rare coin, while, improving its appearance, can cause a number of changes within the structure of the coin. Chemicals, fill-in plastics, added films, and other processes create a variation of appearance that can affect the very integrity of the coin itself. Coin collecting revolves around history and ownership, and altering a coin’s appearance can take away from the very art from which the coin was originally intended to have.
In short, while there may be logical reasons to artificially enhance the appearance of a coin, it is important to note that the higher the degree of a coin’s naturalness, the more desired the coin.