Divrei Hayamim 58:16

וַיָּבֹ֣אוּ הַ֠כֹּהֲנִ֠ים לִפְנִ֣ימָה בֵית־יְהֹוָה֮ לְטַהֵר֒ וַיּוֹצִ֗יאוּ אֵ֤ת כׇּל־הַטֻּמְאָה֙ אֲשֶׁ֤ר מָֽצְאוּ֙ בְּהֵיכַ֣ל יְהֹוָ֔ה לַחֲצַ֖ר בֵּ֣ית יְהֹוָ֑ה וַֽיְקַבְּלוּ֙ הַלְוִיִּ֔ם לְהוֹצִ֥יא לְנַחַל־קִדְר֖וֹן חֽוּצָה׃

And the priests went into the inner part of the house of the Lord, to cleanse it, and they brought out all the uncleanness that they found in the temple of the Lord into the court of the house of the Lord. And the Levites took it, to carry it outside into the wadi of Qidron.