Kelim, Chapter Eight, Mishnah Eight
1) If a sheretz was found in the [place in a stove] where wood is put:
a) Rabbi Judah says: if it was within the outer edge, [the stove] becomes unclean.
b) But the sages say: if it was outside the inner edge [the stove] remains clean.
c) Rabbi Yose says: if it was found beneath the spot where the pot is placed and inwards, the stove becomes unclean, but if beneath the spot where the pot is set and outwards, it remains clean.
2) If it was found on the place where the bath-keeper sits, or where the dyer sits, or where the olive-boilers sit, the stove remains clean.
a) It only becomes unclean only [when the sheretz] is found in the enclosed part and inwards.
Section one: In this section a sheretz is found in the bottom part of a stove, where they put the wood to burn. Rabbi Judah says that the sheretz defiles the stove if it is found within the outer edge of the place where the wood is put and inwards, inside the stove.
The other sages say that if the sheretz was outside of the inner edge, then the stove remains clean. In other words, the debate exists in a situation where the sheretz is found between the inner and outer edge.
Rabbi Yose defines the place where the sheretz can defile the stove in a slightly different manner. If the sheretz is found directly below the place where the pot is placed on top of the stove, or anywhere within this area, it defiles the whole stove. But if it is outside this area, the stove remains clean.
Section two: This mishnah now describes ovens upon which people sit: bath-keepers, dyers and olive-boilers. If a sheretz is found on this place, the oven remains pure. The mishnah explains that the sheretz defiles the oven only if it is found in the closed part of the oven. These workers sit on the outside part of the oven, where it is open to the air. Therefore, the sheretz does not defile the oven. However, Albeck notes that according to the Tosefta, if the sheretz comes into contact with the oven, the oven is impure. It does not convey impurity through entering the oven’s air-space unless it is within the oven.