I get these out of big breaker boxes and switches off industrial equipment. They are 80% siver and 20% cadnium (the cad prevents arc burns). From what I understand, when you heat cadnium the vapor can kill you so be carefull. Also, the smaller ones can be just a thin layer of silver over a steel or brass base so be careful buying them or you can get burned. Saving em up and selling on ebay is probably the best way to go.