From the second a coin has been struck, it is immediately prone to deterioration. This is especially true if the coin is bound for circulation (as opposed to proof coins, which are generally handled with care). Once a coin leaves the dies, it is subjected to being dropped in a hopper, thrown in a bag, transported to a bank, entered into circulation and subjected to the abuse of everyday use. Even if a coin is put aside as a collectible, it may still be cleaned, polished, engraved, mounted or otherwise mishandled. The basic message is that coins do pick up flaws over time—but some are considered less severe than others. This article will describe the various types of marks seen on coins and their impact on grade/value.
BAG MARKS: As the name implies, these are the marks coins obtain from jostling against each other in bags. They are extremely typical, especially on larger and heavier coins. Like all surface imperfections, bag marks will detract from a coin’s grade, but they are considered benign compared to other marks. Reeding marks are a form of bag mark where the reeded edge of one coin indents another.
HAIRLINES: Hairlines are thin, shallow scratches that usually result from wiping or repeated friction. Light individual hairlines usually don’t detract much from a coin’s grade, but a large patch of hairlines is usually a sign of deliberate mishandling. If a coin’s hairlines are too deep, plentiful and/or distracting, they can disqualify a coin from receiving a numerical grade altogether.
ENGRAVING AND GRAFFITI: Obvious deliberate engravings (like initials scratched into a coin) on a coin are viewed as extremely derogatory. The only possible exception would be extremely elaborate/beautiful engravings and a few famous countermarks. Otherwise, such marks are considered tremendous negatives.
RIM FILES: Some coins show signs of having been filed down on the edge. This was usually done to verify a coin’s authenticity (to make sure it wasn’t plated) or to clandestinely shave a little bit of precious metal off the coin. Regardless of why a rim file exists, it will be viewed by numismatists as a major negative and disqualification from numerical grading.
SURFACE DAMAGE: Granted all of the terms previously discussed are technically a form of damage, but this word usually refers to excessively deep or noticeable gouges. Whereas bag marks and hairlines happen as a result of normal circulation, they are common and generally accepted. A severe scratch or major distracting mark, however, would count as damage.