Commentary for Avodah Zarah 103:24

The midrash above says that Deuteronomy 12:2 is referring to vessels—human-made objects. The problem is that the verse explicitly says “places” not “vessels.” The Talmud explains that we cannot take this word “places” at face value for we have another midrash on the same verse (one we saw above) that says that places (“mountains”) cannot be prohibited. Since it cannot mean that Jews must destroy places where idolatry took place, it must mean that Jews cannot use “vessels” that were used in idolatrous worship.

Yohanan did not need to ask about vessels. Since they can be purified in the mikveh, they are also purified when the idol is annulled. But food cannot be purified in a mikveh. So does it become pure when the idol is annulled?