Gas Tank Pellets Buttons????
 

Pulled the gas tank on my 68 today and heard some rattles in there. I found 3-4 pellets or buttons. About the size of a thick shirt button. They look like lead and actually have a small letter stamp on them. Has anyone ever heard these? Or did someone throw them in there for kicks?

I've never heard of that, but this is just a thought. They might have been put in there to act as sacrificial anodes for corrossion protection. Is it possible they are zinc?

Yes they could be zinc. I was thinking of the sacrificial anode idea also. They all look the same.

I've found plenty of metal chunks the size you describe but they were always random in shape which led me to the conclusion that they were just left overs form the soldering of the tank...never seen any with stampings on them

These are definitely cast into a shape. Definitely not left over slag. I wonder if there was some 'snake oil' product in the 70's, protect your gas tank or get 50MPG with these pellets in your tank! I'd take a picture, but no time right now. Since no one has seen these, I guess it's not a rare option!