That beautiful sterling silver, or even silver-plated, punch bowl that Aunt Mildred gave you many years ago is probably less silver and more grayish-black by now if it's been stored where air circulates around it. Sulfur and other invisible elements in the air combine with the silver to create a corrosive product known as tarnish. Over time, tarnish deepens and darkens. Cleaning silver is hard work if the tarnish is built up, but once you've put in the necessary effort, frequent maintenance keeps your silver punch bowl glistening and ready for use.
Heavy Tarnish Buildup Cures
Take the silver punch bowl out of its storage cabinet and soak it in a tub of warm water and a non-phosphate dish liquid to flush out any dust and debris. Rinse the suds away and resubmerge the bowl completely in a container lined with aluminum foil, dull side down. Add a few tablespoons of baking soda and watch as the tarnish disappears. This chemical reaction is one of the safer methods of removing tarnish. Rinse well and dry with a terry or microfiber towel, making sure no water remains in the feet or around the handles.
Do not submerge a piece with decorative additions such as ivory or wood.
Silver-plate pieces should not be cleaned in this manner, because the thin silver coating will wear away.
Beware of commercial silver cleaners containing abrasives. Be sure they're designed to clean silver, not any other metal. Museums use a mixture of a soft abrasive known as calcium carbonate, or chalk mixed with water, which is applied with cotton or a soft cloth. Don't rub too hard with any paste cleanser -- even a mild abrasive can damage silver.
Homemade paste cleansers that mix baking soda and water are safe for small or light tarnish-removal jobs, and toothpaste mixed with water can work too. But don't apply it with a toothbrush, which is too abrasive. Be sure to wash and rinse the punch bowl well after any paste application, and dry it completely with a soft towel.
Don't rub hard at any stage of cleaning -- silver is a soft metal and the harder the scrub, the more silver is lost. Silver-plate is more susceptible to damage from hard cleaning, because the silver coating over a brass or copper base can be rubbed away.
Don't use an old or dried-out commercial cleanser, because the abrasive buildup is more intense and damaging.
Boiling Water and Salt
Add a tablespoon of salt to a pot of water and heat to boiling. Remove it from the heat and let it sit for a few minutes. Submerge the punch bowl in your enamel sink and pour the hot water over it. The tarnish reacts with the hot water and salt, and disappears. Gently wash, using a non-phosphorous dish liquid; rinse and dry well.
Maintaining the Shine
A silver polishing cloth is your punch bowl's, and your, best friend. It's nonabrasive and easy to use; just lightly rub the bowl with it until the tarnish disappears. Doing this frequently prevents heavy buildup, and your cleaning routine takes seconds instead of hours. The cloth is the safest tarnish remover for silver plate as well.
Store the punch bowl in an airtight space and drop a piece of chalk in the bowl to prevent tarnish buildup.