Okay, so it’s not the usual season for extensive housecleaning. That silver flatware does not make an appearance at most picnics. But perhaps you are shining up some earrings or a bracelet to offset a summer tan. But wait, don’t reach for that silver polish!

Commercial silver polishes and creams often contain ammonia, petroleum distillates, sulfur compounds, synthetic fragrance, and other potentially harmful ingredients. Instead, try a more basic and effective way to remove silver tarnish. The first method requires a glass dish, aluminum foil, hot water, and baking soda. Put the tarnished silver into the dish and cover with foil. Add one cup of boiling water with 1/2 tablespoon baking soda. After a few moments - depending on the degree of tarnishing - remove the silver, dry, and buff with a soft cloth

In fact, this same recipe is given as an educational chemistry demonstration, since it relies on basic chemical reaction and electrochemistry. So why does it work? Well, when the silver metal reacts with sulfides in the air, it creates black silver sulfide known as tarnish. Removing the tarnish returns the shiny silver surface - that’s what silver polish does. Unfortunately, abrasive polishes also rub off some of the silver, while dissolving versions also erode some silver.

Another option is to reverse the chemical reaction and turn silver sulfide back into silver. The aluminum and baking soda method does this, without removing any silver. Using hot water speeds up the process. The aluminum foil is a crucial part, since aluminum oxidizes more easily than silver. So the aluminum forms aluminum sulfide, which appears as a yellowish tinge or flakes. At the same time, the silver sulfide becomes silver. This technique produces a little “rotten egg” odour (hydrogen sulfide gas). At the same time, the baking soda reacts with the hydrogen sulfide, making sodium hydrosulfide along with CO2.

When aluminum and silver are touching, a small electric current passes between them, This electrochemical reaction is similar to the reaction in batteries.

Be careful using this method if you have a pattern of raised silver on a darker background, as it will remove the dark contrast. Also be aware that this method is best for small amounts of silver, as sodium hydrosulfide - one of the end products - holds some potential hazards. It should not be heated or mixed with acids, and it can be corrosive to skin or eyes. Take appropriate precautions.

A second similar method involves making a paste of baking soda and water (3 parts soda to one part water). Rub the silver gently with a cloth and some paste. Rinse and dry with a soft cloth. This works equally well with silver and gold, and relies on slightly abrading the surface (so some metal will be lost). Some people also swear by white toothpaste and rubbing.

Be aware that silversmiths are not fond of either baking soda pastes or toothpaste, claiming that they are too abrasive.

For other metals:

If you are looking at dull copper or brass, use a combination of equal parts salt, flour, and vinegar. Usually one tablespoon of each should be sufficient. Rub the paste onto the item, then rinse and dry with a soft cloth. Buffing will supply the shine. Lemon juice and salt, or lemon juice and baking soda are other options.

Pewter items stain easily - especially if they contact acidic, salty, or oily foods. To remove the blackened tarnish, just go to the refrigerator. Take a cabbage leaf and rub it on the pewter, then buff with a soft cloth.

Alas, all that shiny beauty comes at a price. It should be possible to keep your silver and other metals in tiptop shape without using hazardous chemicals. If there are semiprecious or precious stones in your jewellry, check the guidelines before using any techniques. Turquoise, for example, does not like to get wet and may become soft or discoloured over repeated cleanings.