Lay it on top of the other (full) one. You can clearly see it's just missing part of the coin for size comparison. You can clearly see it's nothing more than part of the coin is simply missing. Intentionally removed, worn off, who knows. But looks all post mint. Nothing special.
What is best to use to clean all the oxidation and grime from them? I have several that are badly damaged, and covered in grime and crud
Tell your roommate to put it back where he found it It is not copper only damaged! It's not worth trying to save damaged Copper Plated Zinc Cents.. just spend them!
