How could grease produce a strike through like this? Wouldn't it have to be something more solid like metal scraps?
A strike through can be anything: fabric, metal, grease/debris etc. When the debris clogs the die or blocks the strike action there is nowhere for the metal of the coin to go…Spark
I'm referring to the weak lettering around the edge. During the usage of the die there is a moment where a mint employee will wipe the die down for whatever reason. The cloth has grease on it which will get into the incused areas. After some time and a few wipes the grease becomes compacted and would not allow the letters, numbers and images to form properly.
Your coin is showing signs of some wear. When it was minted it was struck through something like grease. This also causes the weakly struck look that you see, which is affecting the design, letters and numbers on the coin. Welcome to CT.
Struck through grease. In Kennedy halves, grease deposits are often thicker opposite the eagle's breast. Hence the depression on the side of Kennedy's head. Grease of the right consistency tends to migrate toward areas of lower effective striking pressure.
