Shabbos Chart #4

TUMAH OF DIFFERENT VESSELS

		(A) EARTHENWARE AND "NETER"	(B) METAL VESSELS	(C) GLASS VESSELS	(D) WOODEN, LEATHER, OR BONE VESSELS
1)	*MIKVAH* MAKES IT TAHOR	No	Yes	No(3)	Yes
2)	TOUCHING THE *BACK* OF THE VESSEL MAKES IT TAMEI	No	Yes	Yes	Yes
3)	HAS *RETORACTIVE TUMAH* (D'RABANAN) IF RECONSTRUCTED AFTER BEING RUINED	No	Yes	No	No
4)	EVEN *FLAT* VESSELS ARE TAMEI	No	Yes	No	No
5)	MAKES WHAT ENTERS *THE AIR* OF ITS INSIDE BECOME TAMEI(1)	Yes	No	No(2)	No

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FOOTNOTES:
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(1) In a similar manner, if something Tamei enters into it, the Kli Cheres becomes Tamei.

(2) However, from Tosfos (16a, DH Elah me'Atah) it would seem that according to Rav Ashi, it would indeed be Metamei through its air.

(3) This is not the Halachah if the glass was broken and a piece of lead was melted into the hole or crack, because then it is considered to be a metal vessel with regard to all of its laws, according to Rebbi Meir. The reason that it cannot become Tahor through immersion in a Mikvah is because the Rabanan equated it with earthenware vessels. Even though the Gemara later states that the Rabanan equated it with *metal* vessels since it can be fixed if it was broken, nevertheless it can *become Tamei* in the first place only because of its similarity to earthenware vessels (Tosfos, DH Elah Keivan). (However, Tosfos in Rosh Hashanah 19a, DH Yehudah, seems to imply that according to even its very ability to become Tamei is indeed learned from *metal* vessels. According to this understanding, glass vessels *should* become Tahor through immersion in a Mikvah.)