I accidentally made a coffee with milk in a “fleishig” mug. I don’t typically put any meat in the mugs, but they are washed with my meat dishes in the dishwasher etc. what should I do with the mug?
In retrospect, you may still use the mug, because it was only a kli sheini, when the milk was placed inside it. Just wash out the mug well (not together with your fleishog dishes), with soap and water that is not hot .
Rema Y:D 105-3.