brass polish alternatives?

I need to polish a very small amount of brass but I'm too cheap to go out and buy some tarnish remover.

Any suggestions on household products (preferably non-toxic) that might make a good substitute for brass polish?  

Toothpaste, vinegar and salt, lemon and salt, all remove tarnish

toothpaste!?!
neat!  

Cut a lemon, peel it, take a chunk of peel and sprinkle salt on the inside of it. Rub the brass with it. When it's clean enough, turn it over and rub the exterior of the peel on the brass, the oil protects it.
If the brass is really grubby, leave a bit of the pulp in the peel, if it's not, you probably don't need it. Too much acid eats the details on your brass down if you do it too often.

Liz uses ketchup on copper. Works super and you almost always have some on hand.
I suspect it will work well on brass.

Agree with the lemon suggestion - can also used powdered citric acid the same way since many home preservers have a bag of this hanging around.