Disconnect the antenna cables from the Airport card:

If you have an original MacBook Core Duo or Core 2 Duo model, see the first picture, which shows that there are three antenna cables.

If you have a MacBook Core 2 Duo Santa Rosa/Penryn or 2009 model, there are only two antenna cables, and the plug/socket for the black inverter cable is in a different location. There may be a square foam piece over the plug/socket for the inverter board connector.

Disconnect the inverter cable from its socket by inserting a spudger between the right or left ends of the plug and the socket, and prying gently vertically. Do NOT pry up on the socket--you must pull up on the plug alone, vertically out of the socket. Do not pull in the direction of the cable wires or you will tear the socket off the logic board.