Gemara

(Beraisa): Shimon Ben Shetach decreed Tum'ah on metal vessels.

He decreed Tum'ah Yeshanah on them. (If they were broken, and fixed, they are Teme'im like before.)

This was lest people cease to use Mei Chatas to be Metaher from Tum'as Mes [because they do not want to wait seven days].

Question: According to the opinion that it applies to all Tum'os, how can we answer?

Answer (Abaye): He decreed lest they were not broken enough to be Metaher them.

Chulin 107a (Rava): A Kli with a hole that is Kones Mashkeh (through which liquids can enter) may not be used to wash the hands.

(Rava): A Kli that cannot hold a Revi'is of water may not be used to wash the hands.

Parah (Mishnah 5:7): If there is a hole at the bottom of a Kli, and it was plugged with a rag, the water inside is Pasul (one may not be Mekadesh it with ashes of the Parah Adumah), since it is not surrounded by a Kli. If there is a hole in the side of Kli, and it was plugged with a rag, the water inside is Kosher, since it is surrounded by a Kli.

Rishonim

Rosh (Chulin 8:15): If a Kli has a hole, and it holds a Revi'is below the hole, one may wash through the hole, but not through the mouth. Above the hole is not considered a Kli.

Terumas ha'Deshen (261): Semag and Semak say that if a Kli has a hole that is Kones Mashkeh, which is bigger than a hole that is Motzi Mashkeh (through which liquids leave), it is Pasul for Netilas Yadayim, for is not considered a Kli. If it has a hole that is Motzi Mashkeh, and it holds a Revi'is below the hole, one may wash from it through the hole, but not through the mouth. Since the water passes above the hole, it is Pasul. What is above the hole is not considered a Kli. Also Hagahos Maimoniyos says so. The Rambam connotes that a hole that is Kones Mashkeh totally disqualifies. Such a hole is Metaher Kelim used for liquids, like Tosfos says (Shabbos 96a DH ul'Inyan). However, perhaps that refers to a hole in the bottom, so the Kli does not hold a Revi'is above (perhaps this should say "below" - PF) the hole. This requires investigation. The Mordechai says that Tosfos in Chulin says that whether the hole is Kones Mashkeh or Motzi Mashkeh, it is Kosher if he pours through the hole, as long as it holds a Revi'is below the hole. I did not find this in Tosfos there. The Rosh and Tur connote like the Mordechai (Berachos 192). It seems that if a hole is not Kones Mashkeh, they are Machshir even through the mouth. We can say that the Mordechai said that Tosfos is Machshir through the hole for the case of a hole that is Kones Mashkeh, but if it is not Kones Mashkeh, it is Kosher even through the mouth. Since Rabanan argue about this, it seems that we are lenient about Netilas Yadayim. The Rambam and Mishnah (Yadayim 2:4) are Metaher every Safek about Netilas Yadayim. It seems that the same applies to a Safek about whom the Halachah follows. However, if Ge'onim explicitly forbid something, and we infer that one Gaon disagrees, it is hard to rely on this against what is explicit.

Beis Yosef (OC 159 DH DH u'Mah she'Chasav Rabeinu): Why does he say that the Rosh and Tur do not explicitly permit? Surely they consider anything less than Kones Mashkeh as if there is no hole at all. If even then one may wash only through the hole, why did they mention Kones Mashkeh?

R. Shimshon (Parah 5:7 DH Mipnei): The Mishnah says that the water is not surrounded by a Kli, i.e. the hole uproots the vessel from being considered a Kli. Sealing with a rag does not make it a Kli. If the hole is in the side of Kli, is considered a Kli, so one may be Mekadesh in it.

Poskim

Shulchan Aruch (OC 159:1): Netilas Yadayim is only from a Kli. It must hold a Revi'is. If it has a hole that is Kones Mashkeh, even if it holds a Revi'is below the hole, one may not wash from it.

Shulchan Aruch (2): One may not wash from through the mouth above, for what is above the hole is not considered a Kli, so the water does not come from the Kli. One may wash through the hole, since it holds a Revi'is below the hole.

Beis Yosef (DH u'Mah she'Chasav Rabeinu): The Rosh connotes that he discusses a hole that is Kones Mashkeh, like he discussed above. If so, if the hole is not Kones Mashkeh, one may wash even through the mouth. It seems that the Rashba (Chulin 107a DH ul'Inyan) agrees. Even the Kli does not hold a Revi'is below the hole, one may wash from it since the hole is not Kones Mashkeh. In Toras ha'Bayis, he wrote that since a hole that is not Kones Mashkeh is not Metaher the Kli, it is as if there is no hole. However, Semag says that if there is a hole that is Kones Mashkeh, it is not a Kli at all, even if it holds a Revi'is below the hole. If the hole is not Kones Mashkeh, and it holds a Revi'is below the hole, and water comes from the hole to his hands, his hands are Tehorim. However, one who washes from the water that passes around the hole and falls over the brim of the Kli, [his hands are] Pesulim, since above the hole is not a Kli. Below the hole is a Kli, since the hole is not Kones Mashkeh. Also Semak and Hagahos Maimoniyos (6:10) say so.

Magen Avraham (3): Toras ha'Bayis says like it says in Shulchan Aruch. "Even if the Kli was broken, if it was not broken enough to be Metaher it, one may wash from it. We do not divide (the law of) the Kli into two. If a Kli holds a Revi'is, and the hole is not big enough to be Metaher it, one may wash from it (even through the mouth)." The Beis Yosef explained this with difficulty. I explain that if it has a hole that is Kones Mashkeh, one may wash from it if it holds a Revi'is, for this is not Metaher it, e.g. if the Kli is designated for [solid] food. Only a hole that lets out an olive is Metaher it. If the hole is Metaher it, i.e. it is Motzi Zayis, or Kones Mashkeh in a Kli designated for liquids, one may not wash from it even through the hole, for it is a broken Kli. R. Yerucham says so in the name of the Rashba, just he rules unlike his Heter to wash from its mouth if the hole was not Metaher it. The Rambam and Tur rule like this. The Tur says that mere designation for olives does not help, i.e. to wash through the mouth, or when it does not hold a Revi'is below the hole.

Gra (DH v'Hani): The Tosefta (Yadayim 1:4) says that if a broken Kli Cheres holds a Revi'is, one may wash from it. One may wash from a pouch, even if it is broken. R. Shimshon (on Yadayim 1:2) says that it must hold a Revi'is, like it says in Chulin. See Parah 5:7.

Gra (DH Aval): Toras ha'Bayis and the Bach are Machshir (pouring through the hole), like through a spigot.

Mishnah Berurah (10): The Shulchan Aruch rules like the Tur's opinion. Many Poskim disagree, and say that if a Kli Cheres designated for liquids has a hole that is Kones Mashkeh, it is like a broken Kli, and one may not wash from it at all, even through the hole. This is unlike a spigot, which is made for this l'Chatchilah. In any case, if one has no other Kli, one may rely on the Mechaber to wash through the hole. If a Kli Cheres is designated for food, or other Kelim that do not become Tahor through a hole that is Kones Mashkeh, all permit washing through the hole. Below (162:3), many Acharonim conclude that one may wash through the hole only if the hole is big enough so that the water flows through without interruption. If not, it is forbidden, for this is like washing half at a time. This is in pressed circumstances. L'Chatchilah, one should get an intact Kli.

Mishnah Berurah (11): Some Acharonim (including the Bach) say that this is only if it has a hole, but if it is cracked, even if it holds a Revi'is below the crack, even if it is only Motzi Mashkeh, it is Pasul, for it is like a broken Kli, also regarding Tum'ah. This is because the Kli will become totally cracked. The Taz says that a crack is like a hole. We disqualify only if water leaves the crack drop after drop, for this is like Kones Mashkeh. The Chayei Adam says that if one has no other Kli, he may rely on the Taz. It seems that even the Bach holds that a crack is like a hole for Kelim of copper or other metals (such as tin), for they are strong, and a small crack will not lead to a total crack. I say that for a glass Kli, even if a crack is very thin and it is not even Motzi Mashkeh, if it cannot hold hot water like cold water, one should not wash from it.

Kaf ha'Chayim (9): The Shulchan Aruch connotes that if a Kli has a hole that is Motzi Mashkeh, one may wash from it even through the mouth, even if it does not hold a Revi'is below the hole. We require holding a Revi'is below the hole and washing through the hole only for a hole that is Kones Mashkeh. The Beis Yosef says so according to the Rashba. Semag and Semak are stringent. One should be lenient only in pressed circumstances, and in such a case one should not bless Al Netilas Yadayim. One should think the Berachah, or say it without Shem and Malchus. We are lenient about a Safek Netilas Yadayim, for it is mid'Rabanan, but we are stringent about the Berachah, because Lo Sisa (Es Shem Hash-m la'Shav) is mid'Oraisa.