I just took a look at the owners papers for my new 642-1 and it says, "Purchase cleaning supplies . . . that are specifically designated for your type and caliber of firearm. . . . Choice of solvent should be restriced to those products specifically developed for firearms maintenance. Damage to a firearm's finish may occur if these cautions are ignored. Ammoniated solvents or other strong alkaline solvents, should not be used." Pretty obvious that they want us to use specific firearms-intended products and not motor oil or generic things like 3-in-1 or WD-40.