ISO Crocking Cloth /Cotton Lawn Rubbing Fabric For Testing Colour Transfer in Textile Industries. Crocking cloth, also known as cotton lawn fabric or rubbing cloth, is used in a Crockmaster (Crockmeter) to check the amount of dye transfer, following a dry or wet rub fastness test. The dyed sample is rubbed, under controlled conditions, against the white crocking cloth. Subsequently, the degree of color transfer is evaluated using a Grey Scale for assessing Staining. Click for more details.