OK...I found a cheap and easy miracle. 1 part vinegar, 1 part salt and enough flour to make a spreadable paste. Holy crap. I brushed it and before I finished a brush stroke you could see the tarnish disappear. Works on copper and brass and probably other metals. I rubbed it in with a sponge and rinsed it with a garden hose. Took all of 5 minutes. Then spent about 20 minutes with some Brasso and got a good shine. Not a mirror, but nice and clean and shiny.

Got the recipe off some hippy website. I guess they are good for something.