וַיַּ֣עַשׂ כִּיּוֹרִים֮ עֲשָׂרָה֒ וַ֠יִּתֵּן חֲמִשָּׁ֨ה מִיָּמִ֜ין וַחֲמִשָּׁ֤ה מִשְּׂמֹאול֙ לְרָחְצָ֣ה בָהֶ֔ם אֶת־מַעֲשֵׂ֥ה הָעוֹלָ֖ה יָדִ֣יחוּ בָ֑ם וְהַיָּ֕ם לְרָחְצָ֥ה לַכֹּהֲנִ֖ים בּֽוֹ׃ (ס)
He made also ten lavers, and put five on the right hand, and five on the left, to wash in them; such things as belonged to the burnt-offering they washed in them; but the sea was for the priests to wash in.
Rashi on II Chronicles
and five on the left to wash with them This is the sanctification of the hands and feet.