A wear trial of full-length white nylon underskirts was conducted to compare the contributions to discoloration due to changes in the nylon polymer, to the spin finish, to a fluorescent brightener, to the soap used in washing, to skin fat, and to air-borne dirt. The underskirts, in absence and in presence of spin finish and of brightener, were worn according to a schedule and washed in a standardised way using a low concentration of soap. Greyness and yellowness increased steadily, the greyness being greatcr in the upper than in the lower parts of the garments. After the wear trial, retained fat was extracted from the garments with organic solvents, weighed and analysed. The high discoloration found in all garments was due mainly to the absorption of skin fat and soap and the associated retention of particulate dirt. Fat and yellow colcuring matter could be transferred during washing. Spin finish and fluorescent brightener usually only slightly affected the discoloration. There was negligible discoloration due to the storage of the nylon, repeated washing of clean fabric, and repeated exposure to dirty air followed by washing.A laboratory study is reported of the gas-phase chlorination of wool at atmospheric pressure. The influence of chlorine concentration in chlorine-air mixtures, regain of wool, and temperature on the extent of the reaction has been measured. Two small-scale pilot plants for the chlorination of top are described, one for batchwise and one for continuous operation. The washing performance of samples of wool chlorinated in these plants was tested; the results are given in Part I1 of this paper.