WD40 is probably the worst thing you can do to any gun, its water basedWhile attending a gunsmithing course in Louisiana a local PD Detective brought in his S&W model 36 complaining he couldn't eject rounds from the cylinder. He said he routinely sprayed WD40 on the loaded revolver. We removed the cylinder and had to use a wooden dowel to remove the green corroded rounds. Thank goodness he never had to actually fire it.