Grassing (textiles)
Grassing is one of the oldest methods of bleaching textile goods. To bleach linen and cotton-based fabrics, the Grassing method has been used. Linen has long been bleached in Europe with Grassing method. Method. The linens were laid out on the grass for over seven days after boiling with the <nowiki>"lyes of ashes and rinsing"</nowiki>. It was Oxygen of the atmosphere and the oxygen left by the grass was providing whitening action. The cloth becomes whiter day by day until it attains the full whiteness. It was a slow process, but safer for the subjected  material. In chemical bleaching the bleach may harm the cloth too, but in the Grassing it hardly affects the cloth's strength. Bleachfield. Bleachfield was an open area to spread cloth, it was an field near watercourse used by a bleachery. Bleachfields were common in and around the mill towns during the British Industrial Revolution Chemical bleaching. After discovering Chlorine in the late 18th century, when chemical bleaching came into existence, the chemical bleaching rose above Grassing, as it was quicker and possible in indoors. Oxygen bleaching action. It is the conjugated double bonds of the substrate that makes the  substrate capable of absorbing visible light. Hence, it looks yellower and need bleaching. When bleaching action carries out with oxygen, it removes the chromophoric sites and makes the cloths whiter. Oxygen is a degrading bleaching agent. Its bleaching action is based on <nowiki>"destroying the phenolic groups and the carbon–carbon double bonds."</nowiki>. The major source of chemical bleaching is Hydrogen peroxide that contains a single bond, (–O–O–). When breaks give rise to very reactive oxygen specie, which is the active agents of the bleach. Around sixty percent of the world Hydrogen peroxide is used in chemical  Bleaching of textiles and wood pulp.