The word “silver” often conjures thoughts of treasure and very high-value objects. In fact, items made from this precious metal are more common than you might imagine and most people will own something made of silver: a small trophy, a coin, a watch chain or a table ornament or implement. Silver has an attractive colour and will take a high polish. It can be worked in many ways: shaped by hammering or turning, or cast into intricate shapes. It can be embellished by engraving, inset with gems or plated with gold and it is often used in association with polished hardwoods, ivory, or other metals of contrasting colour.
The silver used to manufacture most domestic-type objects originating in the UK is sterling silver. This is an alloy consisting of 92.5% silver and 7.5% copper. Many of the 'silver' objects originating from the Middle or Far East and Central or South America will have a very different composition, usually with a much lower silver content in the alloy. In some cases there is none at all - 'German Silver' is a white alloy made from nickel, zinc and copper. This guidance applies to the care and cleaning of objects which are in sound condition and made only of silver, though the techniques described can often be used when other materials are present.
'Tarnish' appears as gradual discolouration and loss of polish, the metal turning first to pink, darkening to brown, and then to a very dark grey or black with a slight iridescent sheen. This is caused by sulphur compounds in the atmosphere, originating from the burning of fossil fuels and other industrial activity. Humans are also agents in producing tarnish – the salts and greases in our skin are highly corrosive and can mark a polished surface irreversibly.
Where conditions have become more harsh, or an object has been severely neglected, you may also see crusty, green-coloured deposits. These are the corrosion products of the copper in the silver-alloy as it corrodes. There are many causes for this, but common ones are storage in damp conditions or the action of chemicals, especially those from the residues of cleaning compounds.
If the tarnish is light then you may wish to remove it with a commercial silver cleaning cloth. This will remove dust, light sticky or greasy deposits and the dulling tarnish, leaving a brightly polished finish. This works for large areas of plain, undecorated silver, and its use can be a regular part of your general housekeeping routine. Do bear in mind the points above about not doing this too often and only for non-historical pieces; remember to buy new cloths from time to time. Intricately shaped or decorated surfaces will require the use of a liquid cleaner.
If the tarnish is heavy, then a liquid method such as a “silver dip” might be effective. This works by chemically dissolving the tarnish. It creates a very reactive surface however, which will tarnish again quickly, so finish with a silver polishing cloth. Follow instructions on the container carefully: wear rubber gloves and, if you are using large quantities, goggles. Use a fresh solution every time you clean the silver, rinse and dry thoroughly using clean cotton cloths. Maintain the finish with occasional wipe-over with a silver cleaning cloth.
Most modern silver is protected after manufacture with a sprayed lacquer finish. This is usually cellulose nitrate dissolved in organic solvents. Commercial companies do offer a lacquering service, but you should think carefully and take advice before having this done to historic items, and consider the following points:
Conservators specialising in metals have the practical skills and technical knowledge to carry out cleaning, repair and stabilisation of silver items of all periods. Their approach will be based on safe practice and minimum intervention – preserving as much of the original item as possible and retaining all related information and evidence.
Use the Conservation Register to Find a conservator.
© Icon, the Institute of Conservation 2011.
This article offers general guidance and is not intended to be a substitute for the professional advice of an accredited conservator. The views expressed are those of the author or authors, and do not necessarily represent the views of the Institute of Conservation.
The Institute of Conservation would like to acknowledge use of the MGC publication 'Ours for Keeps' in the preparation of this text. The Institute of Conservation and its partners accept no liability for any loss or damage which may arise if this guidance is followed.
The Institute of Conservation would like to acknowledge the support of The Royal Commission for the Exhibition of 1851 in the production of this guidance information. Further information on The Royal Commission for the Exhibition of 1851 and its work is available at www.royalcommission1851.org.uk.