Appears like machine doubling damage on the date, but difficult to tell with the photo. Common cent. Jim
I'm sorry. Had a few drinks last night and got a bit silly. It's really tough to know exactly what caused the damage. Welcome to CT. We do have fun here. Maybe too much at times.
some dirty liquid probably fell on it. If you look at that arc of stain, you could guess that a dime was on top of it (It's not a total circle because it was tilted due to the design) when something else dripped on it causing the stain.