Raw wool contains seeds and other pieces of vegetable matter. Much of this may be removed in scouring and in combing. Combing is not used in woolen system and vegetable matter is only partially removed in carding. Even in some worsted processes, small amount of residual vegetable material is present in the fabric and in such cases carbonizing is essential to remove the residues.
The scoured wool fabric is padded, either in the rope form or in open width, with liquor containing dilute sulfuric acid (5 to 7 % by wt.) at approximately 65% wet pick up. And dried at 65 -90 degree celsius to concentrate the acid. Baking at 125 degree celsius for one minute chars the cellulosic material. The charred vegetable material is brittle and easily crushed on passing the rollers. it can be removed as dust during subsequent mechanical working. After carbonizing the wool fabric should rinsed and neutralized by washing. Such neutralization should be carried out immediately after baking; otherwise fabric damage will occur during storage of wool in such as acidic state. It is convenient to neutralize prior to dyeing but uneven neutralization leads to uneven dyeing’s.