This coin would have made my top 3 coins of 2019. See below for a timeline of my coin misery! I bought this coin at an auction that closed on July 2, 2019. The auction photo did not show signs of bronze disease that I could see. I took my own photos on July 23, 2019 soon after I received the coin. There were some signs of green that were not on the auction picture (note the green in the crack in from of Caracalla's forehead). I do not remember what my level of concern was at the time. I did not like the photos I took (partially because of a carpet fuzzy on the obverse) so I set the coin aside to try again when I had some time. I went to take some additional photos of it today and noted that the coin seems to be suffering from bronze disease that has spread. Based on what I see from the 3 photos (especially the July 23) it seems that the coin had bronze disease when I received it. This is the only logical answer because I am meticulous in my storage. See below for a comparison of the photos (none of which I am happy with, quality wise btw ). Auction house photo take before July 2, 2019 My photo dated July 23, 2019 My photo October 23, 2019 I like the coin a lot and I have hours and hours worth of research into it but I am unsure if I should return it or try to treat it. One thing that worries me is that if I try to treat it and it doesn't work there might be more of an issue with me trying to return it later. The coin wasn't necessarily cheap so it would be a bummer to lose the coin to BD and lose the money that could be spent on further coin purchases. What do you think? What would you? Have you ever had to return a coin for BD?