I agree with Simple Green, first. Then, as suggested, "Bar Keeper's Friend; or perhaps, a product called Zud, and (of course) the old darkroom rat standby, Bon Ami.
In my experience, the Bon Ami in the cans is the least aggresive cleaner of the three powders.
Softest of all is the Bon Ami in the bar form--if it still be made and one can find it.
The latter is what the darkroom rats used to clean and polish ferrotype tins, many of which were stainless steel and did not take kindly to any kind of scratching.