Line a non-metal container with aluminum foil.
Place tarnished silver in – make sure it touches the aluminum foil.
The chemical equation:
Silver sulfide + Aluminum --> Silver + Aluminum Sulfide
Some Side Notes:
After hearing about this demonstration numerous times, I decided to give it a try (and get some pictures so I could share it with you). It worked so well! The yellow that's left on the foil isn't real apparent, although you could see an outline from where things had been sitting. But, what was very apparent was the smell of sulfur, as soon as the solution was poured over the silver. Wow! I wasn't expecting that, but it certainly confirmed that the tarnish was composed of sulfur! I'm now in search of a large enough vat to use to "polish" the teapot that goes with this lid!
One more thing.... when researching the exact chemical equation I learned something else.... traditional silver polishes actually remove small amounts of silver along with the tarnish. This method only removes the tarnish. Seems like the way to go - no polishing and keeps the silver fully in tact!
Presented at the 2003 New Jersey Science Convention.