A dispute on the prohibition of the idol when it's owned by a Jew vs. owned by non-Jew (Rabbi Akiva vs. Rabbi Yishmael). Also, vessels that were used in the "Temple of Onias" -- "chonyo," outside of the Temple, once it had been built. [Note: Historically, the specific temple of Onias was a center of worship for Egyptian Judaism.] Rabbi Yehudah HaNasi forgot (!) the verse from which the external worship was prohibited -- and then he was reminded of it by Rabbi Yosi bar Shaul. Also, the specifics of the Temple - as presented in the tractate Middot - were key in terms of assessing what could and could not be used in the Temple - once they were used unlawfully, even unto the Temple's altar itself (in the time of the Hasmoneans). It was a problem of the stones not being smooth, and so they were hid - but why hide? Why not repurpose them? Plus, the gold of Jerusalem and the coins that were permitted for use.