I just got a similar coin in change today.. large date.. my question is what causes it to turn green-ish?
There are several types of clips, a straight clip, a ragged clip and the most copping is a curved clip. They all fall under the category of incomplete planchet, which is the correct term. Here’s a few examples that I own. First Is the ragged Now the most common, a curved. This is a 1917 Cent. Here is a slabbed one. Notice they give a percentage of the clip. And here is a triple clip. Planchets are made from a sheet. As the sheet moves forward the holes are made but if the sheet doesn’t advance properly a clip will occur. Here is a chart to show that. Hopes this hopes you understand a little more.