PURPOSE: To remove oil and finger mark stain completely from uncleaned Al pipe contaminated with oil or finger marks by passing the Al pipe successively through an alcohol-soluble component-removing tank, a washing tank in boiling CFC, a washing tank with supersonic wave in CFC and a washing tank in CFC vapor, in the order.

CONSTITUTION: For the purpose of removing of removing cutting oil used in the forming stage of an Al pipe to be used for an electrophotographic sensitive body, or finger marks of workers contaminating the surface of the uncleaned Al pipe, the uncleaned Al pipe 1 is dipped in a liquid mixture (a) consisting of ethanol/CFC in 5:100W30:100 proportion contained in an alcohol-soluble component-removing tank 10, and the contaminating component soluble in alcohol is dissolved and removed by applying supersonic wave oscillation generated by a supersonic wave generator 16. The pipe is then dipped in a washing tank 20 contg. boiling CFC heated with a heater 24, further in a washing tank 30 with supersonic wave in CFC installed with a supersonic wave oscillator 36 and a washing tank 40 in CFC vapor wherein liquid flon (d) is evaporated by heating with a heater 43. Thus, the pipe is washed finally with CFC vapor to perform degreasing and washing by removing completely oils and finger mark stain from the surface of the pipe 1.