When the glass globe detaches from the screw socket: 1) turn of the power or at least set the switch in the off position. 2)carwfully jerk the glass bulb free from the socket. You are breaking a couple of thin copper wires. 3) With a pair of pliers, either insulated or wearing insulated gloves, grsp the edge of the metal screw socket and unscrew it. 4) Stuck to tight? bend the edge in more. get a better grip. This will both loosen it and give you better advantage. Still won't move? WD-40. Still won't budge? You need a new fixture and check for water damage as it's rusted in place if not crossthreaded.