Breaking in speaker cables??

Louder means higher voltage. You might try it. It works for me when I (re) solder terminations, but the break-in only takes a 1/2 hour of medium volume playing.

One European cable manufacturer "breaks in" his UNterminated wires by using them as a main cable for a few hours (on a lamp bulb if I'm not mistaken). That's 230V, 50Hz AC.

DON'T DO THIS unless you're an electrician!

Just mentioned it to give an idea of what crazy things we people will do. A cable cooker is more benign & much more expensive:)

Do you need a electrician to plug in a lamp in a wall plug? Just tape the bare end to be safe.

There is no, "positive" side to an AC outlet. There is a HOT leg, and NOTHING will flow, if a wire is connected between two hots of the SAME PHASE. Current will only flow if a NEUTRAL is attached, or if both HOT legs of your incoming 230V service are attached. In either of those cases; there had best be a load connected(ie: lightbulb/230V appliance), else you will have(of course) created a dead short.

Why not just put one end into the amp and the other into the speaker?

"Why not just put one end into the amp and the other into the speaker?"

What's the point of being AUDIOPHILES if things are that simple? We might as well be normal people. I see you have a lot to learn about high-end audio. I would have thought that every Audiophile worthy of the name would know the answer to all this. Oh well, might as well tell you:
Tie one end of the cable to a lightning Rod atop a tall building, the other end to a grounding Rod driven into the earth.( I assume you have a LOT of cable) Wait for a storm, if you live in Texas, you won't wait long, and watch them babies break-in!!