Lov'n the MC-0.5's but - a magnetic question

I'm totally on-board with High Fidelity's MC5's. You can't argue the improvement just 2 make in a system and it's somewhat confusing how additional ones work so well with apparently no diminishing return. In a short 4 week time period, I've added 6 (in increments of 2) to my preamp line and am ordering 6 more today for my amps.

I have one nagging question about regarding how well they work. After reading a review about their cable construction, there is mention that the core wire of each interconnect can't be silver, copper, or gold due to the fact that these metals won't conduct magnetism. I realize this truth. How then, is the MC-0.5 advantageous to a power line since the magnetism should not be able to flow through the system? 

It may be one of those "If I tell you I'd have to kill you" questions.