Bob,
Some small commercial printers may have Linotype metal they don't want. They used it longer than we did in newspapers as they dusted the wet ink with 'gold' flecks for wedding invitations, in a way that doesn't work with offset printing or photocopies. It's got both tin and antimony and a certain hardness IIRC, but maybe not enough if you mix it with soft lead.

Cheers
- Paul