Method of back-pulse flushing clogged pipes, for example in a hydraulic pipe system

Method of back-pulse flushing clogged pipes, for example in a hydraulic pipe system and use of the method. A method for removing liquid from a lumen of a pipe by a back-pulse flushing where carbon dioxide in liquid or supercritical state is added to a pipe, and the pressure is reduced after diffusion of the CO2 through the liquid, such that the pressure reduction changes the CO2 into expanding gas that presses the matter out of the pipe at the same end into which the CO2 was inserted. The method is useful for cleaning long dead-end pipes, for example hydraulic control pipes for valves in offshore installations, especially in oil and gas industry.