bleaching... all sorts of things can do that to a nem... i have had some bleaching do to light... too much light, or too little light can bleach a nem... a lot of LFS sell bleached nems all the time... they think they can live with a cheap florescent tube... but people buy them because they look neon green or pink... LOL...
i remember a bunch of LFS and sponsors would put a picture of a bleach nem saying it was a rare pink e. quad... hahahaha...