Here's a little update... After about a week sitting in DW, I took it out and worked on it a little bit with tooth pick to moderate success (brown stuff ~1/2 gone), and put it back in new DW. Then last night took it out again after another week or so and worked it some more with tooth pick and was really successful in getting 95% of the original brown stuff gone. I'm calling it quits with any more work and saying happily that I am extremely satisfied with the results.
Great job getting the crud off! I'd now try to let it tone a bit. I hear setting a coin in the sun by a window for a few months can add some toning.
Ooo, that's exactly what I want to happen... add a little bit of toning back to it now that it's cleaner. I'll do just that (esp. now that the rain has just passed and the sun is out)!