Scouring/cleaning
Fabrics received as gray cloth have a lot of impurities naturally present in them. These may be oils, waxes and dirty stains acquired during construction of the fabric. Complete removal or cleaning of these impurities is important before applying any other finish. This cleaning is called scouring and is done to all fabrics with the help of soap solutions and chemicals. After cleaning, the fabric becomes smooth, neat and more absorbent
Bleaching
When fabrics are made, they are not white in color, due to impurities and coloring material present in them. To make them white or to dye them in light colors they are bleached. Suitable bleaching agents are used to removing the color from the fabric. Bleaching is done for cotton, woolens and silks. Man-made fabrics do not need bleaching as they are naturally white.
Bleaching has to be done very carefully as the chemical which can destroy the color may also damage the fabric to some extent. Hydrogen peroxide is a universal bleach which can be applied to all kinds of fabrics.
Stiffening
The stiffening means the fabric which is generally limp becomes stiff when a stiffening agent is applied. For stiffening silk, gums are used.
Stiffening gives body, smoothness, and luster to the fabric. This practice is sometimes used to cheat the customer. You must have observed that sometimes if you rub a fabric between your hands, some white powder comes out. It is because the fabric has been over-starched. Interior fabrics are over-starched to look dense and better.