Abstract: A system for degreasing the interior surfaces of kitchen exhaust ventilation ducting includes a number of nozzles connected to piping disposed interiorly and longitudinally to the ducting by a framework. The nozzles are supplied by a high pressure pump through the piping and direct a stream of high velocity fluid against the interior surface of the ducting. Selective operation of the nozzles preferably minimizes pump capacity. Sequencing of selective nozzle operation from top to bottom preferably produces a rolling cascade of high velocity fluid directed against the interior surface of the ducting. The resulting effluent is readily collected from the lower end of the ducting and disposed of in any manner desired.