Abstract: A method for decolorization of a dyed polyester fiber includes: separately providing a dyed polyester fiber stained with a dye, and a solvent capable of dissolving the dye; heating the solvent to produce a fresh vapor of the solvent, the temperature of the fresh vapor ranging between the glass transition temperature and the melting point of the polyester fiber; condensing the fresh vapor to form a condensed fluid of the solvent; contacting the dyed polyester fiber with the condensed fluid of the solvent that has a temperature sufficient to dissolve the dye such that the dye is extracted from the dyed polyester fiber so as to form a dye-containing solution and a decolorized polyester fiber; and separating the dye-containing solution from the decolorized polyester fiber.