(R. Zerika citing R. Yehudah): Beis Hillel only permits the use of earth which had been dug (Deker Na'utz) from before Yom Tov (and only needs to be lifted out), but not that the Aseh of Kisuy overrides the Lav of Yom Tov.

Question: But he will crumble the dirt (Meleches Kesishah)!?

Answer (R. Chiya b. Ashi citing Rav): The earth was already soft, not needing to be pulverized.

Question: But he is making a crevice (Guma, which is Meleches Boneh)!?

Answer: As R. Aba taught that making a Guma where he does not need one is Patur (it is Kilkul, not Tikun).

Question: How does this statement relate to the discussion of the Mishnah!?

Answer (Rabah): The Tana is raising the new matter, that the ashes of a Kirah are not Muktzah.

(R. Yehudah citing Rav): Only ashes made before Yom Tov are not Muktzah.

New ashes are also permitted if they are still hot enough to harden an egg and they may be used for Kisuy ha'Dam (for which they were not designated).

This is supported by a Beraisa, which adds that a mound of earth intended for later spreading (as a flooring) is also considered Muchan for Kisuy.

(R. Yehudah): Even a small undesignated mound may be used for anything, including Kisuy.

(Mar Zutra citing the elder): This is provided that he designated its place.

Question: But the Mishnah must not subscribe to R. Yehudah's permission, since it does not permit Kisuy on a Koy.

Question: If that bothers you, then ask why the Mishnah does not allow Kirah ashes or a Deker!?

Answer: Clearly, we are speaking where he does not have any dirt available.

Answer: Here, too, he does not have a mound!

Question: Then why does the Mishnah speak of a Koy (whose Kisuy is a Safek) if its Din could be taught by a Chayah (which is a Vadai)!?

Answer: The Tana is teaching the form of a "not only."

A Chayah must not be slaughtered if dirt is not available.

Even a Koy, whose Kisuy is only a Safek (and might be permitted owing to Simchas Yom Tov), must not be slaughtered on Yom Tov.

Question: But the Seifah (by telling us that he must not do Kisuy on the blood of a Koy) implies that he had a way of doing Kisuy, then why not do the Kisuy!?

Answer (Rabah): The Mishnah is teaching us that the ashes of a Kirah are Muchan for Kisuy Vadai, not for Kisuy Safek (and the Tana therefore speaks of Koy).

Question: Why should a person (who expects to use his earth for any purpose) not be able to use it for Dam Safek!?

Answer: Since he is making a Guma.

Question: But that is true by a Vadai, as well!?

Answer: There is no Isur of Guma (like R. Aba, above).

Question: Then Koy should also be permitted!?

Answer: We are afraid by the Koy that he will perform Kesishah.

Question: That should prohibit a Vadai, as well!?

Answer: There is less reason to prohibit a Vadai.

Most times the dirt does not need to be broken (Rashi).

Even if it is broken, the Aseh of Kisuy overrides the Lav of Yom Tov (which would not hold if the Aseh is a Safek as by Koy).

Question: But Aseh is only Docheh Lo Sa'aseh when it is b'Idna (he performs the Mitzvah when he violates the Lav) whereas he breaks the clump of dirt before the Kisuy!?

Answer: The Mishnah is speaking where he breaks it simultaneous with the Kisuy.

Question: But Yom Tov (which is both a Lav and an Aseh) should not be overridden by an Aseh!?

Answer (Rava): Chazal were not concerned (when prohibiting Kisuy on the Koy) over Kesishah, but they understood that a person only did Hachanah for a Vadai.

Rava is consistent with his position regarding the limitations of designation.

He taught that earth which was designated for an event which might not occur (a Safek, such as Kisuy Tzo'a) may be used for Shechitah, whereas earth designated for a Vadai (such as Shechitah) may not be used for the Safek use.

Naharblai taught that if the occurrence of the Safek is nearly certain, then the designation for one applies to the other.

In Eretz Yisrael they argued whether a Koy is equated with Tzo'a, or if Koy is more certain a need than Tzo'a (and thus earth designated for Tzo'a could not be used for Kisuy Dam Koy).

We may prove from the above citation that Rava holds that Koy is doubtful and equivalent to Tzo'a.

(Rami bar R. Yeiva): We do not permit Kisuy Dam Koy on Yom Tov lest people come to permit its Chelev (like that of a Chayah).

Question: That should then apply every day, as well!?

Answer: Sprinkling earth on the Dam during Chol could be interpreted as for cleaning up, not for Kisuy.

Question: Then what would be the Din if one slaughtered a Koy during Chol in a place where the sprinkling could not be interpreted as cleaning up (as in a trash heap)?

Additional Question: Why do we instruct the Shochet to cover the Dam Koy after the Shechitah, given our concern that we might come to permit its Chelev!?

Answer: Rather, during Chol people will understand that Chazal were Machmir regarding Kisuy, but they would not make that assumption if they witness Kisuy on Yom Tov.

(R. Zeira - Beraisa): If the blood of a Beheimah were to become mixed with that of a Chayah or Of, it is Asur to do Kisuy (like the Dam of a Koy).

(R. Yosi b. Yosiniah): That prohibition only applies if one scooping of earth will not suffice for the entire mixture of blood.

Question: Is it not obvious that if Kisuy can be done on all the blood at once that it is permitted!?

Answer: We might have prohibited one Dekirah lest the person come to permit two Dekiros.