A method and system for cleaning the perforations of well casings employs a non-rotating tubing string attached to a hydraulic jet carrier body. The carrier body has outwardly extending arms which terminate in spray nozzles, each of the nozzles expelling a stream of fluid under pressure against the well casing with an inertial force. The nozzles are oriented on the carrier body such that the reactive force for each jet is directionally offset with respect to the central axis of the carrier, thereby creating a twisting moment tending to rotate the carrier body about its central axis. The nozzles are located a fixed distance from the carrier body which is between about ½ and 1½ inches from the well casing perforations in use.