We kashered our milchig and fleshing sinks for Pesach. We put inserts into the sinks and during Chol Hamoed we realized that we have been using our milchig sink with the insert to wash our fleischig pots and dishes with hot water. What do we do after Yom tov? Can we continue using the milchig sink or has it become treif? And what would be the best sefer to learn the intricate halachot on keeping a kosher kitchen; preferably in English. Tizkeh l’mitzvos.
You should kasher the sinks after Yom Tov (wait 24 hrs without using the sinks with hot water, and then kasher by means of pouring boiling water), after which they can be used as usual.
You can find a list of relevant books here.