This part of ISO 1833 specifies a method, using dichloromethane, to determine the percentage of triacetate, after removal of non-fibrous matter, in textiles made of binary mixtures of - triacetate or polylactide and - wool, regenerated protein, cotton (scoured, kiered, or bleached), viscose, cupro, modal, polyamide, polyester, acrylic and glass fibres. Triacetate fibres which have received a finish leading to partial hydrolysis cease to be completely soluble in the reagent. In such cases, this method is not applicable.