Pewter is a durable, yet relatively soft metal. Therefore, care should be taken when cleaning pewter not to etch or otherwise damage the finish. Using harsh abrasive cleaners can scratch pewter; acidic cleaners can permanently etch or discolor the finish.
The good news is, pewter rarely tarnishes, unlike silver or brass, and therefore needs very little care to keep it looking its best.
Although pewter is often used for dinnerware, drinkware and tableware, caution should be used when serving highly acidic foods out of pewter items. Just as harsh acidic cleansers can etch and discolor pewter, so can acidic foods, such as citrus fruits, tomato-based dishes and soft drinks.
When pewter is used for serving food and drinks, it is best to wash it as soon as possible after use. Washing in warm water with a mild, bleach-free dishwashing liquid is enough to safely clean pewter. Always towel dry.
If salad oils or other foods have left a sticky residue on your pewter items, it is safe to clean brushed or matte finished pewter with a soft steel wool pad, taking care to scrub in the direction of the brush marks.
Never put these items in a dishwasher. Automatic dishwasher detergents and rinse aids can permanently discolor or damage pewter.
For pewter items with a brushed, or matte finish, dusting occasionally with a soft cloth is enough to clean these items. For brushed pewter items that have become soiled, washing with warm water and mild detergent is best, followed by drying with a soft cloth.
Pewter with a smooth, shiny finished has been polished. To keep polished pewter looking good, regular dusting with a soft cloth, coupled with periodic washing in warm water with a mild detergent and hand drying is usually enough; however, if your polished pewter has lost its luster, look for a commercial pewter polish, usually found in hardware stores, that is specifically marked as safe for polished pewter finishes.
Many pewter items--especially pewter jewelry--have an antiqued or oxidized finish that gives them a darkened, aged look. For most of these items, this is a chemical finish, and cleaning with abrasive or chemical cleaners can remove this finish. Clean these items with a soft cloth, or by washing with warm water and a mild detergent, then towel-drying.