The Levites purified themselves and washed their clothes, and Aaron presented them as a wave offering before the LORD. Aaron also made atonement for them to cleanse them.
Jewish Publication Society of America Version (JPS1917) - Numbers 8:21 >And the Levites purified themselves, and they washed their clothes; and Aaron offered them for a sacred gift before the LORD; and Aaron made atonement for them to cleanse them.