The Pewter FAQ's Pewter may be pitted or stained by acids and other chemicals in some foods, so wash immediately after using. Be careful not to dent or scratch it.
Antique pewter is an alloy of lead and tin.
The lead makes it darken to its characteristic shade. Because of the lead, these antique pieces should not be used for food or beverages. It is lead-free, will not darken, and is safe for use with food. It is a soft metal alloy, and is easily bent, or scratched. Salt, Vinegar, and Flour .