Aluminium foil and vinegar can be used to clean tarnished silver due to a chemical process called ion exchange. A vinegar and salt solution transfers some of the silver molecules to the foil, removing the tarnished surface and showing the bright silver beneath. Since the process uses common household items, you can avoid the expense and potential risk of keeping commercial tarnish-removers around the house and clean silver whenever you need to. This process may clean tarnish from the crevices of raised designs also, so only use it if you don't mind losing the dark areas which emphasise the design.
Pour 1 cup of warm water into a 1-qt. glass or ceramic container. Stir in 1 tbsp salt and 1 tbsp vinegar until they're dissolved.
Add a 3-inch-square piece of aluminium foil.
Submerge the silver that you want to clean so that it weighs down the foil. Make sure both the silver and the foil are completely underwater. Let everything soak for one hour.
Remove the silver and rinse it in clear water. Rub it with a soft cloth to remove the remaining tarnish and dry it with a dry cloth. Discard the vinegar solution.
To clean larger pieces of silver, increase the ingredients and the amount of foil proportionately. If any tarnished places remain, squeeze a little non-gel toothpaste on them, scrub them with a soft cloth, and rinse.
Don't use this method for silver that's cemented together since soaking in the solution may weaken the cement.