Explanation #1 (Rashi): The wholesaler bought from many people, and mixed the Peros together, and he does not know whose they were (the Peros in which the coins were found). We discuss when there is no Siman.

Question: Why don't we establish it to discuss a buyer who is a wholesaler (and he does not know from whom he bought these Peros)?

Answer: The law is not always true in this case. If he found [the coins] before he delayed to mixed with others' Peros, he would be obligated to return them;

However, if one bought from a wholesaler, the wholesaler already mixed them.

Explanation #2: Even without the reason of mixing with other Peros, [our Mishnah] was taught only regarding one who bought from a wholesaler, for he does not know to whom to return, i.e. to the wholesaler or the Ba'al ha'Bayis [who sold to the wholesaler].

Implied question: If it is common for [coins] to fall in grain only at the time of threshing, we have no doubt to say that [perhaps] they are the wholesaler's!

Answer: In any case, he does not know from which Ba'al ha'Bayis the wholesaler bought.

Implied question: According to this Perush, we could have said that we discuss a buyer who is a wholesaler, and the Ba'al ha'Bayis despairs, for he thinks that the wholesaler already sold, and the buyer does not know to whom he should return.

Answer: Also here, it is not uniform. If the wholesaler found it before delaying the time to sell to another, the Ba'al ha'Bayis did not despair, and he must return it.

Reference: In Bava Kama (66a), we say that we learn despair about something stolen from Aveidah.

Question: What is the source regarding an Aveidah itself?

Answer #1: We learn from here. Just like a garment is special, that it has a Siman and the owner does not despair, rather, he demands that [the finder] return it through Simanim (one must return all such matters).

Implied question: If Simanim are not mid'Oraisa, and we return only through witnesses [how can we learn from here]?

Answer: Even so, we learn from a garment that one must return only something that has a Siman, for through having a Siman, he will find witnesses. He will say to them "do you recognize my garment, which has such and such Simanim?"

Also the finder will not take it out to show it to anyone, only to one who gives Simanim. Even though he does not return it to him through [Simanim], in any case it seems that it is his, and he shows it to witnesses.

However, something without a Siman, the finder keeps it, for the owner despaired.

Implied question: Why does the Gemara say that Simanim was taught without need? Through Simanim, people will claim it (like Tosfos explained)!

Answer: In any case, [Simanim] was taught without need, for even had it taught only "there are people who will claim it", still we would know that through Simanim, people will claim it, and the owner did not despair, like I explained.

Answer #2: However, the Yerushalmi learns "what is the source for Yi'ush from the Torah? R. Yochanan said, "Asher Tovad Mimenu" - what is lost from him, and available to others. This excludes this (what is lost to everyone, e.g. an overflowing river took it. Surely the owner despaired, so the finder keeps it.)

Explanation: If Simanim are not mid'Oraisa [one can return a donkey through witnesses who recognize the saddle].

Question: If the shearings are worth a Perutah, obviously (one must return them)! If they are not worth a Perutah, below we exclude that one need not return them!

Answer: This is needed to obligate shearing it in the proper time, even though it is not Shaveh Perutah at the time he shears it.

Implied question: Why didn't he say that "Gam" (regarding Esnan Zonah and Mechir Kelev, it says "Gam Sheneihem") is difficult for Beis Hillel?

Answer: He mentions only animals [that we cannot explain why the Torah wrote them].

Question: We should say that something that we could have learned from a Kal va'Chomer teaches, the Torah wrote it anyway (like we say elsewhere)!

Answer (Ri Kohen): Since "Shor" was written for shearings of the tail, shearings of a Seh are included in "Kol Aveidas Achicha." (We know this without a Kal va'Chomer.)

Explanation: One might have thought that he is liable, for it is included in Kol Aveidas Achicha.

Explanation: This is a Beraisa. (This is unlike Rashi, who explains that this is how Rava established the verse, on 27a.)

Question: Our Mishnah (below, 28b) expounds from this verse that one does not return [to a swindler] even with Simanim!

Answer #1: That is a mere Asmachta, like it taught about this in the Beraisa "after swindlers increased, they enacted [that he must bring witnesses that he is not a swindler].

However, here it connotes that is a proper Drashah, since it says "would you think [to say that you give it to him before he requests it?!" This shows that the verse is truly extra, and must be expounded.]

Answer #2: Our Mishnah discusses when it is known that he is a swindler. Therefore, he needs witnesses. Here, we discuss Stam people.

Explanation: [If he found] the Get tied to a wallet, the finder returns it to the Shali'ach or husband who asks for it, through Simanim on the wallet.

Question: We should prove from here that Simanim are mid'Oraisa! In Yevamos (120a), the Gemara asks from here that Simanim are mid'Oraisa!

Answer: We could establish it when the one who lost found it and recognizes the wallet. Since he himself found it, he is believed. Similarly, we could have rejected there.

Question: It says "Lo Senacheshu"!

Answer: In Shabbos (67a), we say that Darchei ha'Emori does not apply to anything that cures.

Explanation: This does not refer to real Simanim Muvhakim. Rather, they are more Muvhak than the Simanim that his friend gave, e.g. this one says the length, and this one says the width;

Also below, it says "really, he announces a garment, and he did not say Simanim Muvhakim." Also there, they are not real Simanim Muvhakim. Rather, he did not say good Simanim in it, rather like Simanim that it is red or white.