Pewter is all over, and Hallmarked pewter is suppose to be at least 95% Tin. My wife runs with a bunch of gals they call the "Garage Sale Goddess', so we hit a bunch of garage sales every year. She takes me along to drive, and so she can ask me if I can fix the junk she buys, before she gets it home. The best tip I can give you is to hit Estate Sales on the last day, because the people that are running them have about had it with the public by then, and want to be done. They like to talk to folks that want all of anything , whether it be puter, lead, or reloading supplies. Good way to get nice towels for shop rags also. Drives my wife crazy when I cut up perfectly matched sets of towels for shop rags! LOL
If your really interested in Pewter ID in short form, there is a post on CB done by a guy who lists all the names Pewter is sold under, and their Hallmarks in several languages. Once you get a feel for it you'll be surprised what is made of Pewter, some you might even feel guilty about melting.