פירוש על עבודה זרה 104:1

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.