TT #302 · Parshas Tazria · Aliyah 7 · Passuk 58
English: The garment, warp or woof, or any leather article that you wash, if the lesion disappears from it, shall be washed a second time and be clean.
Torah Temimah cites Sifra (Toras Kohanim) for requiring complete removal of the lesion before the second washing.
Sifra — Vayikra 13, Midrash Sefer
English: “The lesion has departed from them” means that it must be removed completely.
Textual derivation
The second washing cannot proceed while any part of the lesion remains; the lesion must have disappeared completely from the article.