china dishes that have a smooth coated finish-unknown if used for milchig or fleishig–never used together–they havent been used in over ten years—-can they be kashered? do they need kashering after such a long time?
They can be used after kashering them 3 times, meaning that each dish should be immersed in boiling water 3 times, but you should wait that the water comes to a boil between each emmersion. The reason for this is, because china is considered an earthenware kli (kli cheres), and chazal said that the absorbed taste of a kli cheres does not come out. There are opinions however that, after 12 months that it is possible to get the absorbed taste out of it by doing hagalah on it 3 times.
Shut R’ A. Eiger 49.