When does an idol become forbidden? From the time it was created or from the time it was worshipped? What about a utensil for idol worship? Rabbi Akiva and Rabbi Yishmael disagree and the amoraim bring proof texts for each of them. Several questions are asked regarding the impurity that the rabbis instituted for items of idol worship. Can the impurity on a food that was offered up to an idol and then canceled by a non-Jew be considered pure or is the law the same as the benefit which is forbidden forever even if the item is cancelled? Can items used in the temple built by Onias (Chonyo) be used in the Beit Hamikdash?