So I am about to send off my iPhone which I just sold. I was wondering what is the best way to send it off and make sure everything on it is wiped clean. Should I restore with my sim card in it, then pull the sim and send it off? Or should I restore WITHOUT the sim and then simply send off? Does doing so one way or the other effect the unlock in any way, or once its unlocked (which I already did) it is unlocked for good?