The generally accepted term for these are "adjustment marks". In the early days of the US Mint, quality control often lacked a certain expertise so the unstruck planchets were sometimes under weight or overweight. So, mint workers were required to weigh each and every unstruck planchet. When underweight there was nothing to do but throw them back in the melting pot (see p.s. below). But when a planchet was overweight, the worker would take a file and strike off some of the metal, a bit at time while reweighing until they cut it down to the proper weight. Now the blank planchet had file marks on it. When the dies raised the impression, often the metal could not flow enough to fill all the file marks. These are called "adjustment marks". I have only seen and heard of these on silver and gold coins, never copper coins. They are an as-minted condition and will never result in a coin receiving a details grade since the marks are not damage. However, many people will not pay as much for a coin with adjustment marks. I for one find a certain charm and historical interest to them. P.S. In the very early days of the mint, there were some rare and more-or-less one-off attempts to increase the weight of a slightly underweight planchet by installing a solid silver plug in the coin.