Shining Copper Bars:I'm wary to use the hazardous copper polish from the hardware store both because I don't feel like exposing myself to it and also because I am a cheapskate. I've found that a little table salt and Heinz white vinegar does the trick nicely, along with a standard dish-washing sponge. Be sure to let the salt crystals melt before rubbing gently or else the scratching will be deeper than otherwise. Or if you don't care about hairline scratches, I think the abrasion of undissolved salt helps get stubborn tarnish.
1. Get clean sponge ($1), table salt (free at White Castle and other fine dining establishments), Heinz white vinegar ($1), and a clean surface.
2. apply a sprinkle or two of salt to the surface of the bar
3. pour a liberal amount of vinegar over it for 1-2 seconds
4. allow a couple seconds for salt crystals to dissolve
5. gently rub with the soft side of the kitchen sponge
6. rinse off the bar in warm running water & gently dry
7. repeat as needed
