Tarnish Can be Easily Removed
Tarnish is a chemical reaction that causes a discolouration to the outer layers of certain metals. The most common problem that's encountered with tarnish is in relation to sterling silver. Tarnish is caused primarily by sulpher containing gases in the air.
Sulphur dioxide (a chemical compound of suphur and oxygen) is a common air pollutant that comes from burning fossil fuels. It's also produced by most vehicles, domestic boilers and industrial machinery that burns fuel with a high sulphur content. Burning fossil fuels provides us with about 80% of the energy we use.
Fossil fuels which include oil, coal and gas are formed from the fossilised remains of plants and animals that lived millions of years ago. This is how the name 'fossil fuels' came about. It's also produced naturally by active volcanoes.
The process of tarnish which is also known as oxidation affects copper, brass, sterling silver, aluminum and several other metals. As the thickness of tarnish increases the colour changes. What begins as a subtle yellowing on the surface of sterling silver will change to reddish brown to blue and finally black. Interestingly the yolk of an egg which has a high sulphur content will cause a silver spoon to tarnish almost immediately. Sulphur is usually the cause of any 'rotten egg' smells.
Other factors can speed up the process of tarnishing some of which include include humidity, perspiration which contains salt which is a corrosive, the latex in rubber gloves and also wool. Paper, cardboard and foam packaging can also speed up the rate at which certain metals tarnish if any moisture happens to be present. For this reason silica gel sachets are often included in packaging because they absorb moisture.
Tarnish is simply a film which covers the metal and does not cause any long term damage. In fact it forms a seal which protects deeper layers from becoming tarnished. It can usually be quite easily removed.
A silver polishing cloth can be used to remove tarnish from sterling silver jewellery whilst various polishes can be used on household items. Solutions are also available but should be used with caution because some contain chemicals which may leave marks on the metal.
Pure silver is fairly resistant to tarnishing but the alloys used to improve its strength and durability are not.