❖ Liquid preparations contains pyroxylin or nitrated cellulose in a mixture of 3 parts ether (such as ethyl ester) and 1 part alcohol (ethanol) ❖ Intended to be applied to the skin by means of soft crush or suitable applicator. ❖ Ether and ethanol when evaporated, they will leave a film of pyroxylin on the surface. Ex. Duofilm- for warts