Three observations,
first, nobody has mentioned corrosion, which can occur to copper cables over time;
second, to Guidocorona, last time I checked coal or whatever fuel is used to power generators and does not cause impurities in the electron flow, no matter how dirty. However, the dirty coal might contribute to air pollution, greenhouse effect and global warming (which is bad for tube amps);
and finally, to Gunbei, I have not seen any pictures posted of your girlfriends but after the mental picture your post provides, I have made a note to self not to buy any used cables from you :>)