Mine tend to attach out of site, and then stretch up to the light. I found if I take the rock they're attached to and expose their foot to the bright lights, they'll try to walk away from it, at which point its pretty easy to pry them off. Before they start to move on their own however, they're on there very tight and I am not sure I could get them off without tearing the foot (i.e. killing the 'nem).
jds