All your pottery shards look so beautiful laid out like that. That would look great in a display case.
I'd hate to be the one to give you "unsafe" advise there are several ways of cleaning coppers, best advise is practice on newer copper coins that might not be of value to you. There is a "cleaning and preservation" forum to help give you ideas. There are a wide opinion on the safe way of cleaning. You might have to come up with your own way.