Conservators are using purified specific enzymes to dissolve organic substances when treating delicate fabrics. By careful selection of an enzyme that will attack a stain but not the fibre historic textiles are treated locally by using a poultice gel. Tests are described on 10 samples on which each of three enzymes were applied to prove that the enzymes do not engage in non-specific attack. The treatment of a 6th century coptic textile is discussed. Photographs, references.