Comentário sobre Ohalot 5:3

מצלת על הכל – [if affords protection] on everything that is in the upper chamber, for it interposes in front of the defilement.

If [the pot] was whole:
Bet Hillel says: it protects all [from uncleanness].
A vessel of earthenware can protect everything [in it from contracting impurity], according to Beth Hillel.
Bet Shammai says: it protects only food, drink and earthenware vessels.
But Beth Shammai says: “It protects only food and liquids and [other] vessels of earthenware.”
Bet Hillel changed their opinion and taught as Bet Shammai.
Beth Hillel said to them: “Why?”
Beth Shammai said to them: “Because it is [itself] impure with respect to an ignoramus, and no impure vessel can screen [against impurity].”
Beth Hillel said to them: “And did you not pronounce pure the food and liquids inside it?”
Beth Shammai said to them: “When we pronounced pure the food and liquids inside it, we pronounced them pure for him [the ignoramus] only, but when you pronounced the vessel pure you pronounced it pure for yourself and for him.”
Then Beth Hillel changed their mind and taught according to the opinion of Beth Shammai.
Section one: In this scenario instead of the pot having a hole in it, as it did in yesterday's mishnah, it is whole. According to Bet Hillel (at least at first) the pot protects the contents of the upper story from becoming impure.
Section two: Bet Shammai holds that the pot only protects things that cannot be purified in a mikveh, such as food, drink or earthenware vessels. Things that can be purified in a mikveh are not protected. The reason for this is a bit complicated and is explained more thoroughly in Eduyot 1:14. Below, to aid in understanding today's mishnah, I have replicated that mishnah in its entirety and I have also replicated my commentary (which I wrote over 8 years ago!). Note that in both mishnayot Bet Hillel changes their opinion and rules like Bet Shammai.
According to Numbers 19:15, a clay vessel that is covered with a lid prevents impurity from entering inside of it. If this vessel is found in a room with a dead body, which would normally cause everything in the room to be impure, the clay vessel and all that is inside of it does not contract the impurity. Beth Shammai and Beth Hillel argue about what types of things which may be inside the clay vessels are not impure. According to Beth Hillel any object inside the vessel is pure. Beth Shammai holds that only food, liquids and other clay vessels remain pure; non-clay vessels would be impure.
Beth Shammai explains that we can assume that the clay vessel has been touched by an ignoramus (am haaretz), a person who does not strictly know or observe the laws of ritual purity. It is assumed that the am haaretz makes the vessel impure. Since an impure vessel does not prevent the impurity from entering, the things inside of it are impure.
Beth Hillel responds to Beth Shammai by pointing out that they did indeed accept that the food and liquids inside the vessel were pure. If the clay vessel does not prevent impurity from entering, why should anything inside of it remain pure?
To this question Beth Shammai responds that when they stated that the food and liquids were pure they meant for the am haaretz himself and not for the haver (a person who scrupulously observes the laws of purity and indeed eats only pure food). Beth Shammai assumes that a haver will not borrow any of these things from an am haaretz, since they cannot be made pure (a clay vessel cannot be cleansed of its impurity). Therefore Beth Shammai can pronounce these things clean, knowing that they will never come into the hands of a haver. However, when Beth Hillel pronounced everything inside pure, they were in essence declaring it pure for both the am haaretz and the haver. Beth Hillel had implied that even metal vessels, inside the clay vessel, remained pure. A haver might borrow metal vessels from an am haaretz, with the intent of immersing them to cleanse them of their impurities. However, this immersion will only cleanse them from light impurities and not from impurity contracted from a dead body. Therefore, a haver might borrow them thinking that he could cleanse them and in reality he could not. Due to this problem, Beth Hillel retracted their opinion and taught like Beth Shammai.

אינה מצלת אלא על האוכלים ועל המשקים ועל כלי חרס – he (i.e., the School of Shammai) is speaking about the pot of those who are illiterate. And the reason of the School of Shammai is that the vessels of the illiterate/עם הארץ are impure in regard to a person who a חבר/member of the order for the observance of Levitical laws in daily intercourse, and every impure vessel does not interpose in front of the defilement. And because the illiterate holds his vessels as pure, we state to him that he protects over food and drink and earthenware vessels that are in the upper chamber, that for himself alone that we declare them pure, for those who are members of the order for the observance of Levitical laws in daily intercourse are separate/keep aloof from them and from their contact, for without this, all of their food would be impure. But the other vessels that have purification in a ritual bath/Mikveh, if they will purify them, he (the person who is illiterate) can lend them to a חבר and he would use them with immersion [in a Mikveh] alone, without sprinkling [of ashes] on the third and seventh days.