Okay, my red book is here but I haven't looked at it yet. In the meantime this one, with the missing L on the front, and the faded words I guess maybe is grease? But the the piece of the N on the back, I don't understand. Thanks!
I don't remember how I got it. I haven't bought coins for a very long time. Probably not from circulation though.
The front is from grease, just as you mentioned. The N on the reverse looks like it took a a hit on the lower right side. Copper is soft and easily moved. It looks like it was pushed to the left. If the area in question is higher on the left side then that's probably what happened.
Then the reverse is damaged. Personally, I'd keep the coin due to the nice effect the grease had on the obverse. Nice job.