copper tubing catching fish?

[jason]

How are people using copper tubing in tying on for big fish? What is the purpose? Is it protecting the line some how? I would love to know! It's had my curiosity all week when a couple of guys came in to the local plumbing store to get some because they were after giant blue cats.

 

[Rum Buddies]

not sure what a blue cat is, but I've heard of pouring lead into copper tubing and making a jig out of it. Apparently the copper and lead react together in saltwater and create a charge that bottom fish like.