The TERELENA treatment and process are applicable to both textures and staple polyester; they permanently modify the physical character of the fiber by creating many micro-cavities which greatly increase the surface area and consequently the surface tension. TERELENA is more than a simple process for improving drape, soft hand and achieving a silk like depth of luster. TERELENA treatment by extracting polyester form the surface of the fiber to form micro-cavities causes a reduction of fabric weight. The technician operating the system can set the parameters values which provide the complete uniformity, reproducibility of the terelena process namely a bath concentration, absorption of alkaline solution, reaction temperature, reaction time and fabric characteristics.