Stainless steel is a alloy of iron and more than 10% chromium. This means that stainless steel is highly resistant to stains and rust, though fingerprints show fairly clearly against its shiny patina. When making stainless steel, a thin layer of chromium is added to the outside to make it even more stain resistant, though this layer can and will come off over time causing stainless steel to act like regular steel.
Most people have lots of stainless steel around in their houses, since stainless steel is durable, and therefore used to make lots of things. Stainless steel typically gets oily streaks and discoloration, and since it's all over people's houses, here is how to make stainless steel shiny again.
First of all, a great way to remove streaks out of stainless steel is to rub it down with olive oil; this causes the oily streaks to become uniform and shiny again. Club soda can also be used to remove discoloration caused by heat, and streaks. To polish the surface and get it to shine a solution of white vinegar and water can be used.
When taking care of stainless steel it's important to remove salty or acidic grime from off the utensil before washing it, since if it sits around with that on the surface, it could corrode the protective surface. Stainless steel can be washed in a dishwasher, or by hand, but if washing the stainless steel with real silver, make sure they don’t touch because stainless steel can ruin silver. Occasionally, stainless steel will take up a bluish cast, this is easily removed with silver polish. Never use harsh abrasives or steel wool on stainless steel, as this could remove the protective coating. Commercial stainless steel cleaner is also available.
Never boil water in a stainless steel pot to the point that it all boils up, this causes burned discolored spots in your pots. Since stainless steel heats unevenly look for pots that have a copper coating on the bottom that will cook more evenly. If scorched spots do occur, make a paste out of baking soda and water, or ammonia and rotten stone; and scrub lightly with that. Club soda can also be used.
Infromation from http://doityourself.com/clean/stainlesssteel.htm