Keilim 3:5-6

Keilim 3:5

Let’s say that someone coated an unbroken vessel; Rabbi Meir and Rabbi Shimon say that it is susceptible to ritual impurity. The Sages, however, say that if he coats an unbroken vessel, it is not susceptible to ritual impurity, but if he coats a cracked utensil, it is. The same applies to a gourd that is used as a vessel.

Keilim 3:6

Regarding grass that is used to line casks, whatever food or liquid touches it is susceptible to ritual impurity (because the lining is part of the earthenware cask). The lid of a jar is not considered attached. The food or liquid that touches the exterior coating on an oven is susceptible to ritual impurity (because the coating is considered an integral part of the oven).