Modern pewter is a soft metal, an alloy made with tin that is hardened with the addition of copper and antimony. Originally, pewter was hardened with lead. After long-term exposure to lead was discovered to cause brain disorders, its use in making pewter was discontinued. Antique pewter pieces continue to be in demand as collectibles. Lead-based pewter pieces, which become very dark as they tarnish, and lead-free pewter, which tarnishes slowly, have different cleaning requirements.
Clean the pewter in a dishpan filled with warm, soapy water to remove dirt and oil. Blot it dry with a soft cloth.
Clean darkly tarnished pewter with a paste made from whiting and boiled linseed oil. Rub it onto the surface with a piece of 4/0 steel wool. If the pewter has a dull finish, make a paste from rottenstone (decomposed limestone) and boiled linseed oil. Rub it onto the pewter with a soft cloth. Polish brightly finished pewter by using a soft cloth to rub a paste of whiting mixed with denatured alcohol onto the surface.
Wash the pewter piece in hot, soapy water to remove all traces of the polishing paste. Rinse the item in hot water and dry it thoroughly.
Gently dust the pewter item with a soft cloth. This step is often all that is needed to keep lead-free pewter in good condition.
Wash pewter in warm, soapy water if it has been used with food. Dry gently with a soft cloth.
Mix 1 tsp salt, 1/2 cup flour and 1 cup vinegar into a paste. Rub the mixture into the pewter and rinse.
Wash the pewter piece in warm, soapy water once more, and dry it thoroughly.
Make only enough polishing paste for one use. Place a small amount of the dry ingredient in a small bowl and mix in small quantities of the liquid ingredient until a paste forms. Rub pewter in only one direction when polishing. Some pewter enthusiasts suggest that the best way to clean pewter is to rub the surface with a fresh cabbage leaf.
Do not use silver polish to clean pewter. Use caution in deciding whether or not to remove the dark patina of antique pewter, as it may decrease the value of the piece to collectors. Do not use lead-based pewter for serving or eating food or drink. Do not leave acidic food in or on pewter pieces for more than six hours, as it can cause discolouration. Do not soak pewter pieces in water for long periods of time, and do not wash them in a dishwasher.