Repair of pot metal jewelry

I would appreciate any on repairing old, pot metal
jewelry. What is pot metal? Techniques or books on 'how to'. 

It’s just cheap white metal.

I think people who do repair it use soldering irons and low temp
solder.

I don’t think there are any books.

Elaine
http://www.CreativeTextureTools.com
Hard to Find Tools for Metal Clay