Hello guys, I post this in the Ancient Coins forum because it's rather a question of conservation. I bought a German taler that was probably in the earth for a long time. The coin looks quite fresh, but maybe chlorargyrite and corrosion are issues. I cleaned it in an ultrasonic bath with hot soapy water for a while, but the result was minor. These coins were minted in Goslar as propaganda for a Protestant alliance between Hesse-Cassel and Saxony. The alloy should be almost pure silver. Are there serious ideas for further conservation or experiences with NGS, the conservation service of NGC? Thank you in advice and greetings from Germany Alex
You might consider posting this question and your photos on numismatikforum.de where there are over 100 pages of discussion (at least in the Roman forum) on coin cleaning.
Examine the surfaces closely to first determine if there is any subsurface activity (pitting) beneath heavy toning spots. If so, it's probably best to conserve it. If you can convince yourself that the coin is not being consumed, you might reconsider surrendering the obvious originality of the coin.
