Midrash su Levitico 11:35

1) (Vayikra 11:32) "And all (vessels) upon which there falls of them (sheratzim) in their death shall be tamei." Of what is this verse speaking? If of their death, this has already been stated (Vayikra 11:31). If of ever min hameth (a limb of a dead animal), this is stated below (Vayikra 11:35). It must be speaking, then, of ever min hechai (a limb of a living animal, [and "in their death" signifies the death of the limb]). (But why is a verse needed for this?) Is it not derivable a fortiori? viz.: If a beast, whose blood was not equated with its flesh (to confer tumah), ever min hechai of it confers tumah, then a sheretz, whose blood was equated with its flesh, how much more so should ever min hechai of it confer tumah! (Why, then, is the verse needed?) No, if this is so with a beast, it may be so because it confers tumah by being carried. Would you, then, say the same for a sheretz, which does not confer tumah by being carried, (but only by being touched)? Since it does not confer tumah by being carried, (I would say that) ever min hechai of it does not confer tumah. It must, therefore, be written "And all (vessels) upon which there falls of them (sheratzim) in their death shall be tamei" — to include ever min hechai.

1) (Vayikra 11:35): "And all that there shall fall of their carcass (that of sheratzim) upon it shall be tamei": Of what is this speaking? If of their death (i.e., touching the carcass itself) this has already been mentioned (Vayikra 11:31). If of ever min hechai, this has been mentioned above (Vayikra 11:32 [see Section 6:1]). It must be speaking, then, of ever min hameth (a limb of a dead animal).

2) "of their carcass": not of the bones, not of the teeth, not of the claws, and not of their hair. An oven or a stove, if whole, it is tamei, and if severed, it is clean. From here they ruled: An oven which came in parts from the workshop — if he made frames for it and placed frames upon it, (it being clean), it (now) acquires tumah. If he removed the frames, it is clean; if he (afterwards) returned the frames, it (remains) clean. If he plastered it (after returning the frames), it (again) acquires tumah, and he need not heat it (to render it susceptible of acquiring tumah), for it has already been heated (in the workshop). (Vayikra 11:35): "an oven or a stove shall be torn down": If it were whole, it is tamei, and if it were severed, it is clean. From here they ruled: If a stove were tamei, how is it cleansed? It is divided into three, and he scrapes off the plaster (coating) until it is on the ground. R. Meir says: He need not scrape off the plaster and it need not be on the ground, but he diminishes it (from) four tefachim from within. R. Shimon says: He must move it (from its place and separate the pieces, and if he wishes, he may rejoin them).