I had purchased this same set from UC Berkeley's Lawrence Science Museum only about six years ago and still have those coins in olive oil. I compared this set with that one and these are almost half the size and almost everyone of them are half the size! While it's still fun to clean them and discover what I have I wouldn't buy these from Amazon again since they are so mall and frankly most of them won't yield anything identifiable in the end which is the whole point of the process. Very disappointed.