It obviously needed some cleaning up and had about an inch thick layer of ash on the bottom of the lid so I know it was frequently used at one time. I did some googling to find the best method to clean copper. I ended up trying salt and lime. It did make it cleaner, but no more so than I think plain old water would have.
I imagine it will find a place on a bookshelf in the basement when it is completed (whenever that happens!)