This fellow named "Moritz" sent us some pictures claiming that his Wii Nunchuck cord was discoloring after being used. I have one word for Moritz... "Cheetos". Seriously chief, I would like to join you in fussing that there is some sort of electro-statawhatical charge that was causing discoloration on your Wii Nunchuck, but I'm thinking a little handwashing before play would clear most of this nonsense up.
Oh sure I suppose there is always the outside chance that you're living near Chernobyl or something along those lines, but I'm thinking that you're cord problems have less to do with Nintendo and more to do with Frito Lay.