The magnetic stainless steels used in firearms construction need to be kept clean and should not be oiled or otherwise coated with organic matter, except for lubrication. These stainlesses are best cleaned with acid solutions, usually based on nitric, citric, or oxalic acids. Most commercial stainless kitchenware cleaners are based on oxalic acid and work well on magnetic stainlesses in firearms. Just wear gloves.
Lubrication of all stainless alloys is a nightmare. Light duty lubrication can be effected with pure paraffin wax, cut with tolulene. The tolulene evaporates and leaves a thin wax film on the bearing surfaces. Carefully limit application to areas that actually need lubrication. More demanding bearing surfaces should be lubricated with oils or greases containing molybdenum disulphide or ZDDP. It is important that stainless lubricants be devoid of active sulphur. Active sulphur compounds are commonly used in lubricants intended for regular steels. You choose the viscosity, and whether an oil or grease carrier, based on the bearing surface clearances, along with temperatures. The most extreme lubrication of magnetic stainlesses is effected by copper plating. Copper plating is used on some hot running stainless surfaces in military autocannons - reciprocating and revolver.