My mother made me polish it, because we had gas stove, and sulfur tarnished the pewter. When my mother died, my father just threw it away.

Ouch! The proceeds from selling that pewter would have been considerable .. as noted in CapK's post the "good stuff" costs a bomb these days.
A friend sold her 100-year-old pewter charger (which she bought years ago for $50) and the proceeds paid her round trip ticket from east to Hawaii -- first class!