From: Rabbi Moshe Sofer
To: Unknown recipient
The Chasam Sofer undertakes a close textual analysis of the Ba'al Ha'Itur's ruling in Hilchos Basar B'Chalav, identifying scribal errors in the received text. He demonstrates that after milk was cooked in a meat earthenware pot with bitul b'shishim, the Itur permits continued use for milk but not alternating back to meat; if pareve was cooked instead, the pot becomes neutral and either type may subsequently be used. These emended readings resolve the difficulties raised by the Tur and Beis Yosef.
Source: Shu"t Chasam Sofer YD §84