An oven of stone or of metal is tahor, but [the metal oven] is tamei as a metal utensil. [If] it developed a hole [or] became damaged [or] cracked [and] one made a [clay] coating for it or a supplement of clay, it is tamei. How large must the hole be? [Large] enough for the flame to pass through. And the same applies to a stove. A stove of stone or of metal is tahor, but [the metal stove] is tamei as a metal utensil. [If] it developed a hole [or] became damaged [or] cracked [and] one made feet for it, it is tamei. If one plastered it with clay, whether on the inside or on the outside, it is tahor. R’ Yehudah says: On the inside it is tamei, but on the outside it is tahor.