Acid Fiber Rinse - Fragrance Free will neutralize all caustic residues and rinse away the detergents trapped deep in the carpet fiber. Acid Fiber Rinse - Fragrance Free helps guard the carpet against re-soiling and to prevent browning after the carpets have been cleaned.  Use this product when zero residue is desired. Acid Fiber Rinse - Fragrance Free AID is safe for 5th Generation Stain-Resistant Carpets. Formulated with anti-wicking agents.