Apparatus for efficient cleaning of downhole equipment in boreholes, especially oil and gas wells drilled offshore from floating drilling vessels. The apparatus is a wash tool having an elongated central body with a longitudinal bore therethrough. A plurality of integral, outwardly-extending blades radiate outward from the central body. Wash ports extend radially from the longitudinal bore through the body of the blades, to the outermost surface of the blades and exiting at that point. Spiral or straight blades may be employed. A reduced diameter, extended nose portion is attached to the lower end of the tool. Removable jet nozzles may be installed in the wash ports near the outermost blade faces, to create a high velocity wash stream.