PURPOSE: To smoothen the finely scratched and rugged surface of a body to be washed such as a thin Al alloy cylinder as well as to remove dust, lubricating oil, rust preventing oil, etc., sticking to the surface by jetting fine resin heads of a specified diameter together with high pressure water.

CONSTITUTION: When a body 22 to be washed is washed by jetting high pressure water, fine resin beads of ≤30μm, preferably ≤20μm average diameter are jetted together with high pressure water from a jetting device 9. The finely scratched and rugged surface of the body to be washed such as a thin Al alloy cylinder can be smoothened, dust, lubricating oil, rust preventing oil, etc., sticking to the surface can be removed and uneven coating with paint can be remarkably suppressed when the body is used as an electrophotographic sensitive body.