Caring for your Silver
The typical corrosion product found on silver is dark brown, black or occasionally has purple-blue tones, commonly called tarnish. This corrosion product is not passivating, that is, the presence of tarnish doesn't stop the corrosion process continuing underneath. Because it is rare for corrosion to occur evenly across the surface, the presence of pollutants such as acids found on fingerprints can cause pits to form under the surface layer of tarnish. These will not be apparent until the surface is cleaned.
Ceramic ewer with corroded silver 19th century mounts, before treatment (left) and after treatment (right), 1520. Museum no. C.2008-1910, © Victoria and Albert Museum, London
Silver is particularly susceptible to sulphide initiated corrosion - if you dip a silver spoon into an egg yolk, it will tarnish almost immediately. This was why horn spoons were often used for eating boiled eggs.
Before attempting to clean your silver, please read Cleaning metals: Basic Guidelines
The golden rule is 'gently does it'. As you clean, consider the overall appearance of the piece. In some cases, such as pieces with relief decoration, removing all tarnish can leave a piece looking lifeless. You don't necessarily want a spotless surface. Step back at regular intervals and look at the object as a whole - you may wish to leave some tarnish behind to visually define the design.
- Swab surface with methylated or white spirit to remove grease and dirt - some tarnish may also be removed.
- If tarnish remains, try gently rubbing a silver cloth over the surface - this has mild abrasive particles embedded in it. To get into small corners with the silver cloth, cut out a small square, make a cotton wool swab, wrap the silver cloth round the swab and use the swab to push the silver cloth into the small areas. It can be helpful to moisten the silver cloth with methylated spirit. After using the silver cloth, rub over the area with a swab moistened with alcohol to remove residues.
- If tarnish still remains, try a mild abrasive paste, cream or foam. Make a swab, moisten it with distilled water and pick up a little of the cleaning product. When the swab turns black, change it for a new one. Rub gently over the tarnished area in a circular motion. Remove silver foam residues with a swab moistened with distilled water. Residues can be difficult to remove and you may need to repeat this step.
- Swab lightly with methylated spirit. If the object is going on display, you may wish to gently rub it over with a clean dry silver cloth, which incorporates a tarnish inhibitor, or use a coating.
Silver dips can seem like an easy alternative to polishing. However, they remove the corrosion products by chemical action and tend to over-clean. They remove all corrosion and can leave the surface looking 'lifeless'. Since they react with the silver component of the silver corrosion product, they can also attack the silver of the surface of the object. Removing residues can be difficult because you need to avoid immersing objects in water. If there are any lead solder repairs on your piece, silver dip will turn them black.
Remember, not all silver was intended to be polished, for example matte surfaces or niello, a dark material pushed into engraved areas. Know your object before you start as these finishes are easily damaged.
Silver can also be deliberately 'oxidised', that is, a dark surface is chemically produced on the surface. This was particularly popular as a finish in the 19th century, although it is quite rare for it to survive intact, as it is easily polished away by over zealous cleaning. The example shown is made of silver, with some areas gilded (known as parcel gilt), and other areas darkened or oxidised.
Silver gilt carries a silver mark. Silver tarnish can develop on the gilded surface through minute gaps in the gilding. Silver gilt is cleaned in the same way as silver, although a very cautious approach should be taken because the gilded layers are thin, relatively soft and are easily polished away.