פירוש על עבודה זרה 104:4

If the food is itself worshipped, for instance idolaters bow down to a four-pack of really good beer (hmm, now why would I think of that), there is no question that when the food is annulled as an idol, it becomes pure.

The question is only about foods offered to an idol. R. Giddel said that things offered to an idol can never be annulled. Therefore, this food will definitely always remain prohibited. And thus if it is prohibited, we might say that since it cannot be annulled, it also cannot be purified. Or we might say that since its use is prohibited by the Torah, it cannot be annulled. But its impurity is only of rabbinic status, and therefore maybe it could become pure.
The question, alas, remains unanswered. I think by now you are getting the point with these questions. They are theoretical discussions about annulling idolatry, the purity and impurity of idolatry, and the difference between idols themselves and things used in their worship. They are not answered because this is theoretical halakhah, not practical rulings. The various aspects of the question are far more important than any possible answer.

Yose b. Shaul does not consider the Temple of Onias to be a place of idolatry, but nevertheless, it is still prohibited for priests to serve there. Any priest who did so may not serve in the Temple in Jerusalem. The question R. Yose is asking is whether this applies to the vessels as well. Or were only the priests penalized because they decided to serve in this Temple?

Alas, Rabbi knows the answer, but does not remember how to prove it.

Both sages here refer to a verse from II Chronicles about the vessels that were defiled by the wicked King Ahaz. To both sages, this situation is parallel to the situation of vessels used in the Temple of Onias. The question is what did these people do with the vessels? According to R. Yose, they immersed them in a mikveh and then used them again. The same could be done with the vessels in the Temple of Onias. In contrast, according to Rabbi, they removed them and replaced them. Thus the vessels used in the Temple of Onias cannot be used in Jerusalem.

Rabbi’s opinion might be supported by a tradition that the Hasmoneans (the Maccabees) stored away (put in a geniza) the stones from the altar which the Greeks had defiled through idolatry.

Papa finds a verse that says the Hasmoneans had no choice but to hide away the stones, for the verses from Deuteronomy would not allow them to do anything else.
In contrast, there is no verse to prove that the vessels used in the Temple of Onias are prohibited.

The Talmud asks why they could not just break the stones and then make personal use out of them. We can understand that they could not use them in the Temple service. But this does not mean that they are prohibited from personal use. The same thing occurred with coins after the Temple was destroyed. People feared that any such coin came from the gold and silver stolen from the Temple. But then they found a verse that said that once robbers (Greeks/Romans and other idolaters) enter the Temple, the objects in the Temple become “profane” and therefore permitted in personal use. So why not say the same thing about the altar?

The Talmud now explains why the coins could be put to personal use but the altar-stones cannot. The coins belonged to the Temple and were holy. But they were not used to worship God. Therefore they can be put to personal use. But the altar-stones were used in the Temple worship. Therefore, it would not be right to use them for personal needs.

One who is engaged in idolatry can annul an idol that belongs to him and one that belongs to others. However, a Jew cannot annul the idol of an idolater.
If one annuls an idol, all of the things that go with the idol, for instances the plates used to make offerings to it, are also annulled. Since these things are ancillary to the main idol, they are affected by its change of status. However, if one annuls the things that pertain to the idol, without specifically annulling the idol, the idol is still forbidden.

According to the Mishnah, which was taught by Rabbi when he was older, a non-Jew can annul the idol of another idolater, but not of a Jew. But when he was younger, Rabbi said that an idolater could annul even an idol made by a Jew.
Hillel explains that an idol fully owned by a non-Jew must be set aside, as we learned earlier from this verse. However, if the idol is owned jointly by a Jew and non-Jew it can, according to Rabbi in his youth, be annulled by the non-Jew.

When he was younger, Rabbi thought that since the idol was owned jointly by the Jew and non-Jew, the Jew was worshipping it on account of the sanctity ascribed to it by the non-Jew. When the non-Jew annulled it, the Jew would no longer accord it any sanctity and therefore it is permitted.

When he got older, perhaps more cynical, he believed that the Jew worshipped the idol on his own account. Therefore, the idolater’s annulment would not be effective and the idol would remain prohibited.

The Talmud now offers a different context for R. Hillel’s statement. Obviously, a Jew cannot annul the idol of a non-Jew. Why would the Mishnah need to state this? The answer is that the idol was owned jointly by both parties. The Mishnah teaches that while the Jew cannot annul the part owned by the non-Jew (this is obvious) the non-Jew can still annul his own part in the joint ownership.