Kelim, Chapter Twenty, Mishnah Two
1) A bagpipe is not susceptible to midras uncleanness.
2) A trough for mixing mortar:
a) Bet Shammai says: it is susceptible to midras uncleanness ,
b) And Bet Hillel says it is susceptible to corpse uncleanness only.
3) If a trough of a capacity from two log to nine kav is split, it becomes susceptible to midras uncleanness.
4) If he left it out in the rain and it swelled it is susceptible to corpse uncleanness alone.
5) [If he left it out] during the east wind and it split, it is susceptible to midras uncleanness.
6) In this respect the law is stricter in the case of remnants of wooden vessels than in [that of such vessels] in their original condition.
7) It is also stricter in regard to the remnants of wicker vessels than [to such vessels] as are in their original condition, for when they are in their original condition they are insusceptible to uncleanness until their rim is finished, but after their rim has been finished, even though their edges fell away leaving only the slightest trace of them, they are unclean.
Section one: A bagpipe is not intended for sitting, and therefore it is not susceptible to midras uncleanness.
Section two: According to Bet Shammai, a trough meant mainly for mixing mortar is also used for sitting and therefore it is susceptible to midras impurity. But Bet Hillel holds that it is not meant for sitting and therefore it is susceptible only to other types of impurity, such as corpse uncleanness. It is not susceptible to midras uncleanness.
Section three: A trough that is large enough to hold between two logs of liquid (1/2 of a kav) and nine kav and then is split, is subsequently susceptible to midras impurity because it can be used for sitting. Note that when it was used to hold liquids it would not have been used as a seat and therefore it would not have been susceptible to midras impurity.
Section four: If he leaves it out in the rain, it will swell and the split will be repaired. It will now be possible to again fill it with liquids. At this point it will be susceptible to corpse uncleanness, but not to midras uncleanness because it won’t be used as a seat.
Section five: If he again leaves it out and a dry east wind comes along, the split will again prevent it from holding liquids. At this point, it will go back to being able to be used as a seat and it will be susceptible to midras uncleanness.
Section six: The mishnah now notes an oddity with regard to the impurity of the remnant of wooden vessels. In their original condition, they would not have been susceptible to midras uncleanness, but when they are cracked they become susceptible.
Section seven: The mishnah notes another case where the law is stricter with vessels later in their existence than it is when they are first produced. The manufacturing of a wicker vessel is not considered complete until its rim is finished (see 16:2). But once their manufacturing is complete , their outer edges can completely wear away and the vessel will still be susceptible to impurity. When we think about it, this makes sense. When we buy something new, we expect it to be in mint shape. We wouldn’t buy a pair of shoes with worn-out soles. However, once we own a pair, we will hold onto them even after the soles, or other parts of the shoe show considerable wear.