“Anciently, a fuller was one who cleansed and whitened garments. ‘The process of fulling or cleansing clothes consisted in treading or stamping on the garments with the feet or with bats in tubs of water, in which some alkaline substance answering the purpose of soap had been dissolved’ (Peloubet, 203–4).
“Christ’s blood is the only ‘fuller’s soap’ strong enough to remove all stains of sin from those who repent and fully accept his atoning sacrifice (1 Ne. 12:11; Mosiah 3:11–18; Alma 5:27; 13:11). … However, the blood of Christ will have no cleansing effect upon the wicked, for the stain of sin shall remain on their garments (D&C 29:17)” (Brewster, Doctrine and Covenants Encyclopedia, 195–96).