PURPOSE: To give high rust preventive power to iron-base sliding parts and to improve lubricating property thereof in a real sliding system by cleaning the parts with an inorg. alkali aq. soln. and then repeating cleaning twice with an org. alkali aq. soln. containing ethanolamine and thioacetoamide as coexisting components.

CONSTITUTION: A spherical graphite cast iron member is selected as a sliding part to the cleaned. First, this part is subjected to primary cleaning with inorg. alkali aq. soln. This treatment is performed with using 5% sodium hydroxide soln. for 5 minutes. Then the secondary cleaning treatment with org. alkali aq. soln. is performed with using a soln. of 3% triethanolamine + 12% thioacetoamide. Further, the tertiary cleaning treatment with org. alkali aq. soln. is performed at 75°C with using a soln. of 3% triethanolamine + 12% thioacetoamide. Then the cleaned part is dried with hot air at 110-120°C.