I don't know how to get the stain off, as the beauty of stainless, is that it doesn't tarnish or stain, however, I know that it will stain if you spill a strong base (like drain cleaner) on it. Anyway, my point is, when you do get it clean, use a different detergent in your dishwasher. I expect it is the detergent that is causing the stain.
Put a piece of foil in your sink, plug it, run really hot water, add baking soda and salt. All pieces must touch foil. Test a piece first. Good luck I just did all mine after being in storage 20+ years. 3 batches of stuff and it is gleaming brightly. Good luck. (09/30/2009)
For stainless, there's a product called "Bar Keepers Friend". It's like a cleanser and I use it all the time. Use a cleaning cloth, or something used for Teflon, and put a little of the cleanser on it and rub. It's a great product. Bon Ami will do the same, I just like the Bar Keepers better. (10/01/2009)