(Mishnah): The Shi'ur for a bone is to make a spoon;

R. Yehudah says, it is to make a Chaf (this will be explained).

The Shi'ur for glass is to scrape the end of the spindle;

The Shi'ur for a pebble or stone is to throw at a bird [to chase it away];

R. Eliezer ben Yakov says, it is to throw at an animal.

(Gemara): What is Chaf? It is a lock.

Question: R. Yehudah contradicts himself! (Here, he obligates only for a bigger Shi'ur. Regarding a reed, he is stringent for the smaller Shi'ur to measure a child's foot, even though it is not so common!)

Answer (Mishnah): If the Chafin (teeth of a key) were removed, it is Tamei due to the holes. If the holes were sealed, it is Tamei due to the Chafin;

There, Chaf is what sticks out (the teeth. Will you say that) here Chaf is the lock?! (Rather, surely also here Chaf is teeth of a key, and R. Yehudah's Shi'ur is smaller than Chachamim's. We explained this like PNEI MEIR, NO'AM YERUSHALMI.)

(Mishnah): The Shi'ur for glass is to scrape the end of the spindle.

Question: A Mishnah there (17:5) says that the Shi'ur for broken glass is in order to cover a flask, and here you say so (to scrape the end of the spindle)?!

Answer #1 (R. Acha citing R. Maisha citing R. Kohen citing Rabanan of Kisarin): There we discuss thick glass, and here we discuss thin glass.

Answer #2: There we discuss [Heter to] move it, and here we discuss [the Shi'ur to be liable for] Hotza'ah.

The Shi'ur for a pebble or stone is to throw at a bird.

(Shimon bar Ba citing R. Yochanan): This is to throw at a bird from the back [and it will hit it,] and it will feel it.

And similarly, [R. Eliezer ben Yakov says] to throw at an animal from the back, and it will feel it.

(Beraisa): Prepared stones (the sharp edges were smoothed) the size of an olive, a nut, and an egg, one may take them [into the privy] and clean his legs [after a bowel movement].

R. Yishmael b'Rebbi Yosi says in the name of his father that one may take in up to a handful.

(Rav Yehudah): Baisus ben Zunin was sitting and learning in front of Rebbi. He said, do we say so? Must one sit and weigh by hand [to ensure that the stones are the right sizes]?!

Rebbi: Everything is permitted [to take in his hand], except for what he takes in a Kli.

(R. Ila citing R. Yanai): [A stone is permitted up to] the size of a leg of a small spice mortar.

(R. Yosah): They said only about a [small] mortar [for grinding] one spice, but not for spices.

(R. Ila citing Reish Lakish): If grass grew on a stone, one may take it and clean his legs with it [on Shabbos], and one who detaches from it on Shabbos is Chayav Chatas.

(R. Chiya - Beraisa): Earthenware of any size, one may not clean with it.

(R. Yosi bei R. Bun): This is not only earthenware, rather, even handles of barrels, and anything that enters a fire and leaves (i.e. it is made through fire -RIVIYAH Sof 224).

Note: It is difficult to explain "enters a fire and leaves'' to mean that it does not burn, for the primary matter used to clean was rocks!

(R. Yosi ben Yosi): A stone that someone else cleaned with it, and [a collection of] water less than 40 Sa'im, one may not clean with it (perhaps a snake put venom in it).

(R. Chananyah citing R. Mana): Water that a dog licked, one may not clean with it.

Support (Beraisa): One may not clean with [something in - PNEI MEIR] a dog's mouth, or in front of a dog, or with water that a dog licked, or water less than 40 Sa'im.

[Water] used to wash a sewage pipe or that people bathed with in a bathtub is harmful to the anus.

(R. Yosi bei R. Bun citing Rav Huna): Five matters were said about a sharp reed - one may not slaughter with it, one may not circumcise with it, one may not clean his teeth with it, one may not cut with it meat on the table, and one may not clean himself [in the privy] with it, for Ru'ach Ra rests on it.