(R. Yochanan): (The Mishnah taught (see earlier Bechoros 36(e)) that Beis Shammai say that one should not transfer the Kedushah of Ma'aser Sheni onto gold Dinars. Beis Hillel permit it.) Beis Shammai was only referring to afterwards, when he had already transferred the Kedushah from the produce onto the silver; but even Beis Shammai permits transferring from the produce straight onto gold coins.

What's Beis Shammai's reasoning? (The pasuk states (Devarim 14:25), "And you shall turn it into money'') - (The Kedushah of) produce may be transferred to money but not from that money to other money. (Note: The commentators make many rearrangements to the texts of this and the coming entries, as indicated.)

Question: The next Mishnah teaches - If one exchanges copper coins of Ma'aser Sheni for a (silver) Selah etc. This means that one may exchange many copper coins for one silver Selah. Why then did Beis Shammai (permit this if they don't permit exchanging money for money)?

Answer: (According to Beis Shammai, it is in fact permitted to exchange money for money, but) once the Kedushah has been transferred to silver coins, it can no longer be transferred to other coins.

(R. Shimon ben Lakish): (Disagreeing with R. Yochanan) Beis Shammai disagree both at the beginning (and prohibit redeeming produce directly onto gold coins) and afterwards (meaning when he had already transferred from the produce onto silver coins, he may not then transfer onto gold coins).

What's Beis Shammai's reasoning? The pasuk mentions redeeming onto silver, which excludes gold.

Question: Perhaps it means silver but not copper. But doesn't the next Mishnah teach, "If one exchanges copper coins of Ma'aser Sheni (for a Selah etc.; meaning that the produce had originally been transferred from the produce onto copper)?

Question: What's Beis Shammai's reasoning (to exclude only gold but not copper)?

Answer: Silver and copper are the same (as they are both commonly used as currency, so when the Torah mentioned silver, it was excluding another metal, namely gold).