Keilim 26:9-27:1

Keilim 26:9

If a hide contracted midras impurity and the owner intended to use it to make straps or sandals, then it is purified as soon as he puts the knife to it; this is the opinion of Rabbi Yehuda. The Sages, however, say that it isn’t purified until he has reduced it to less than five handbreadths (about 15”) in size. Rabbi Elazar bar Rabbi Tzadok says that even if one made a handkerchief from a hide, it remains impure but if one makes a handkerchief from a mattress, it is purified.

Keilim 27:1

Cloth is susceptible to five types of impurity, sackcloth to four, leather to three, wood to two and an earthenware utensil to one. An earthenware utensil is only susceptible to impurity as a receptacle; an earthenware utensil that has no concavity is not susceptible to impurity from its exterior. Wood exceeds this in that it is also susceptible to impurity as a seat. Similarly, a wooden slab with no rim is susceptible to impurity but one of earthenware is insusceptible. Leather exceeds this in that it is also susceptible to impurity as a tent. Sackcloth exceeds this in that it is also susceptible to impurity when woven. Cloth exceeds this in that it is also susceptible to impurity when it is only three fingerbreadths by three fingerbreadths.