Carpet dyeing should be left to the professionals, according to Phoenix Brands, the manufacturer of Rit dyes. Proper application and setting of carpet dye requires high temperatures, high pressure, special chemicals and surfactants.
On nylon or wool rugs, Rit dye can be used to spot-dye a worn area. Care in matching the color, applying the dye evenly and blotting excess moisture thoroughly are important. Even with care, the process might not be satisfactory, and the carpet may have to be redone by professionals. Polyester cannot be dyed at all. Carpets or rugs with rubber backing should not be dyed, because the rubber absorbs the dye but does not retain it. Over time, the color is likely to bleed onto the carpet or flooring.