Related על פסחים 30:1

Rabbi Yehuda says in the name of Rabban Gamaliel, two disqualified loaves of thanksgiving offering (see Lev. 7:12-14) were placed on top of the Temple portico. As long as they were placed [on top of the portico], everyone could eat unconsecrated food [containing leaven]. When one was removed, everyone (i.e., the Kohanim) could eat Terumah [containing leaven]. When both were taken away, they burned this one and that one (i.e., unconsecrated food and Terumah). They burned uncertain Terumah (i.e., Terumah whose purity status is uncertain), impure [Terumah], and pure [Terumah] all together, the words of Rabbi Meir. And the Sages say, uncertain [Terumah was burned] by itself, and pure [Terumah] by itself, and impure [Terumah] by itself. Said Rabbi Shimon, Rabbi Eliezer and Rabbi Yehoshua did not disagree about the pure or about the impure [Terumah], whether we burn this one by itself and that one by itself. About what did they disagree? About uncertain [Terumah] and about impure [Terumah], for Rabbi Eliezer says, this one is burned by itself and that one is burned by itself, and Rabbi Yehoshua says, both [are burned] together. Said Rabbi Yosei, the conclusion does not follow from the proof. [What is the proof?] Meat that was rendered impure by a secondary source of impurity [and then made contact] with meat that was rendered impure by a primary source of impurity, both of them are impure, only that this one is possesses a higher degree of impurity, and that one possesses a lower degree of impurity. And so too with oil that became disqualified [through contact with] a tevul yom (i.e., one who has immersed himself but remains impure until sunset) or [by contact] with a candlestick that was rendered impure through death-impurity -- both of them are impure, only that this one is possesses a higher degree of impurity, and that one possesses a lower degree of impurity. And I say that Terumah that became impure through a secondary source of impurity is burned along with Terumah that became impure through a primary source of impurity, even though we are adding impurity onto impurity. And [with respect to] uncertain [Terumah] and impure [Terumah], I say that if the uncertain is burned along with the impure, its impurity is removed from it. Beit Shammai say, we do not burn pure meat with impure meat, but Beit Hilel permit it.