40 most of the power fluid supplied to flow path 48 is directed to annular chamber 61 via radial ports 47 and longitudinal openings 52 a portion of the power fluid exits from jet nozzles 62a and 62b to cause rotation of housing 50 and nozzle body 60 relative to inner mandrel 45 the major portion of the power fluid exits from jet nozzles 63 to remove undesired downhole deposits fig1 shows tubing 23 with an outside diameter only slightly smaller than the inside diameter of casing 22 for many well completions there may be a substantial difference in the size of the downhole well flow conductors nozzle body 60 can be selected to have jet nozzles 63 optimized to clean the relatively small inside diameter of a typical production tubing string or optimized to clean the relatively large inside diameter of a typical casing string an important advantage of the present invention is the ability to insert a work string and cleaning apparatus 40 with relatively small outside diameters through tubing 23 to clean the relatively larger inside diameter of casing 22 below the lower end not shown of tubing 23 the speed of rotation of nozzle body 60 is a function of the size of jet nozzles 62a and 62b fluid flow rate through flow path 48 the type of power fluid downhole well fluids and the characteristics of bearing means 70 71 and 72 power fluid discharged from cleaning apparatus 40 is.