וְכָל־בֶּ֧גֶד וְכָל־כְּלִי־ע֛וֹר וְכָל־מַעֲשֵׂ֥ה עִזִּ֖ים וְכָל־כְּלִי־עֵ֑ץ תִּתְחַטָּֽאוּ׃ (ס)
And as to every garment, and all that is made of skin, and all work of goats’hair, and all things made of wood, ye shall purify.’
Read kabbalistic (mystical) interpretation of Numbers 31:20: and classical mystical sources.