My mom has been staying with us and she brought a glass mug from her house. She does not keep a Kosher home. She ate soup out of the mug using a meat spoon. How should we handle this situation? Would the spoon need Kashering?
From your question I am assuming that the soup was pareve, but not milky. The spoon does not need kashering, because the taste inside the milky mug, would only be nat bar nat, and the mug is only a kli sheini, and we can asume the mug was also not a ben yomo.