Method and system for clearing a pipe system from its contents, the pipe having a proximal end and a distal end, the method including providing an air supply to the pipe system at the proximal end by applying an air pressure decreasing from an initial pressure as the bulk of the pipe contents get discharged gradually at the distal end for obtaining a contents flow in the pipe system. The method further includes determining a volume of air supplied to the pipe system by the air supply, determining an estimated contents travel speed from the volume of the air supplied to the pipe and regulating the air supply to the proximal end of the pipe for obtaining a predetermined pipe contents travel speed using the estimated contents travel speed.