Remove Tarnish Without Using Toxic Chemicals
Place a piece of aluminum foil in the bottom of a shallow dish. (I use a glass baking dish.)
Set the tarnished item directly on the aluminum foil; it has to be in contact with the aluminum.
Heat a quart of water to boiling in a saucepan.
Set the pan in the sink and slowly add 1/4 cup baking soda. Be careful, because it might fizz up and spill over, which is why you add the baking soda slowly & in the sink. Stir until the baking soda is dissolved.
Pour the water into the dish until the tarnished item is immersed. Slightly tarnished pieces will return to silver almost instantly; badly tarnished items will take longer.
You can also use this for flatware or silver/silverplated dishes. Very badly tarnished pieces will look ruined and scare the living heck out of you. (Seriously.) All you have to do is get a little baking soda on a soft, 100% cotton pad, and *gently* buff the silver. The dull grey and residual black will fall away, and the silver will be nice and shiny again, though it may have some "water spots" or "pits" from the tarnish - tarnish is destructive and eats into the silver, just like rust is destructive and eats into steel. For larger pieces, just use more water. The ration of water to baking soda is one cup of soda for every gallon of water.
Why does it work?
Tarnish is composed of silver sulfide, a mix of silver and any sulfur it comes into contact with thru contact with the air and other objects. It basically eats away the surface of the silver. Most removal methods involve removing the tarnish AND the silver that has been destroyed by it. Instead of doing that, this method converts the tarnish back into silver thru an electrochemical reaction. Sulfur more easily attaches to aluminum than it does to silver. The baking soda and hot water are the catalysts for the chemical reaction that causes the silver sulfide atoms to react with the aluminum. Give it a push with a tiny electrical charge (generated between the silver and the aluminum), and the sulfur atoms let go of the silver to go bond with the aluminum instead. Think of it as a choice between one bite of chocolate cake and the whole piece...which would you go for? Apparently, sulfur atoms are no different than you or I. And that, in a simplified nutshell, is why this works and is less damaging to your sterling silver pieces than dips or polishes!