Old pewter is an alloy of tin with some lead. Modern pewter uses tin with copper, antimony and/or bismuth and no lead. The metal is blue-grey in colour and generally has a dull finish.
Pewter was widely used for tankards and other drinking vessels, but also for plates, cutlery and jewellery.
Use of pewter was common from the Middle Ages until cheaper glassware appeared in the 18th and 19th centuries.
Old pewter contains lead and is therefore toxic; this was the reason for the change in ingredients.
Modern pewter can be washed by hand in warm, soapy water. Rinse it with fresh water, wipe with methylated spirits, and then dry and polish thoroughly with a soft cloth. You may use wax as a protective coating.
Antique pewter is not meant to look like silver. To clean and polish pewter giving a dull finish, rub gently in one direction with a paste of tripoli (rottenstone) and boiled linseed oil. For a satin finish, rub in one direction with a paste of whiting and denatured alcohol. When clean, treat it in the same way as modern pewter.