I found this cleaner a few years ago, and I recommend it to everyone, since it seems like a lot of people have never heard of it.  You can use it to clean your nice stainless steel pans, and it makes them nice and shiny, but you can also use it on copper. porcelain, grout and glass.  In fact, nothing cleans my Pyrex baking dishes better than this stuff.  I have also used it to clean my coffee cups clean.  I get it at Sur La Table in Chestnut Hill, but Target now carries it.