I knew being a collector of bronze coins I’d eventually run into bronze disease, especially living in humid Georgia. Well, I believe my baduila nummus may have it. This powdery white substance is on the sides of the coin and looks like it’s spreading. I find it a little ironic with the corona pandemic one of my coins is now sick. Anyway any advice is appreciated and make sure to post any Ostrogothic/Germanic coins you have.
Bronze disease is usually light green and powdery. There have been several threads posted about how to recognize and treat it lately.