Reports the results of the first stage of a major project currently in progress at the British Museum. The aim of the project is to evaluate the effect of aqueous, solvent, and mechanical cleaning on woven textiles made of natural fibers so that the most effective and least damaging processes for textiles in various states of degradation may be identified. Modern undyed cotton, wool (Doctor's flannel), linen, and silk have beem immersed in tap and distilled water, standard textile washing solution, nonionic detergent, and saponin. The effect of rinsing in running water was also evaluated. Treated samples were examined by eye and by optical microscopy. Measurements were made to determine changes in dimension, color, molecular weight, and strength. The results suggest that silk and linen are less stable to aqueous washing than cotton and wool. Standard textile washing solution was the most effective washing agent for cotton, linen, and wool, while saponin was more suitable for silk. Fast flowing tap water was the most damaging treatment for all samples.