Parashas Bamidbar
וְדִשְּׁנ֖וּ אֶת־הַמִּזְבֵּ֑חַ וּפָרְשׂ֣וּ עָלָ֔יו בֶּ֖גֶד אַרְגָּמָֽן׃
They shall remove the ashes from the [copper] altar and spread a purple cloth over it.
Torah Temimah points to R’ Yehudah — TT (verified).
ודשנו את המזבח — תניא, ר׳ יהודה אומר: מהו ודשנו את המזבח? זירוון.
English: “And they shall remove the ashes (dishnu)” — it was taught: R’ Yehudah says: What is “dishnu”? Clearing / removing the ash.
Custom
Chazal clarify that “dishnu” means the clearing of the ashes from the altar.