This project was something I never tried before: unbending a hammered medieval silver coin. This coin has been posted at CoinTalk before (https://www.cointalk.com/threads/a-fun-lot-of-silver-roman-and-medieval-coinage.343992/). In my opinion, the coin has three issues: It's bent quite badly There is a deep scratch, probably caused by digging the coin (and thus causing problem 1) The patina is uneven and 'spotty' So, first a detail image of problem 1: A high-definition image of the obv/rev (note the deep scratch and the uneven patina) Unbending silver hammered coins should be done with caution. I followed this approach https://www.metaldetectingworld.com/cleaning_coin_p24_bent.shtml. After these steps, I ended op with a (almost) perfectly flat coin.