An account is given of a microscopical study of the behaviour of water-soluble substances (salt arid sugar) on wool fibres when they are immersed in charged or batch dry-cleaning liquors. The effects observed depended on the water contents of liquor and fibre, but aqueous drops commonly grew around the dirt that dissolved in them; these then decreased in size and disappeared. Salt did not appear to build up in the charged liquor but was transferred from regions of the wool with a high salt content to regions containing less salt.