Мишна́ к Бамидбар 31:55

Cloth is susceptible to five categories of uncleanness; Sack-cloth is susceptible to four; Leather to three; Wood to two; And an earthenware vessel to one. An earthenware vessel is susceptible to uncleanness [only] as a receptacle; any earthen vessel that has no inner part is not susceptible to uncleanness from its outer part. Wood is subject to an additional form of uncleanness in that it is also susceptible to uncleanness as a seat. Similarly a tablet which has no rim is susceptible to uncleanness if it is a wooden object and insusceptible if it is an earthenware one. Leather is susceptible to an additional form of uncleanness in that it is also susceptible to the uncleanness of a tent. Sack-cloth has an additional form of uncleanness in that it is susceptible to uncleanness as woven work. Cloth has an additional form of uncleanness in that it is susceptible to uncleanness when it is only three by three fingerbreadths.

Cloth is susceptible to midras uncleanness when it is three handbreadths by three handbreadths, and to corpse uncleanness when it is three fingerbreadths by three fingerbreadths. Sack-cloth when it is four handbreadths by four handbreadths. Leather, five handbreadths by five handbreadths. And matting, six handbreadths by six handbreadths. [All of these] are equally susceptible to both midras and corpse uncleanness. Rabbi Meir says: what remains of sack-cloth is susceptible to uncleanness if it is four handbreadths, but when in its first condition [it becomes susceptible only after its manufacture] is completed.