Here's my contact cleaning job on my passenger side seat switches. The seat became completely inoperative... except for "forward", which was great until the seat was all the way forward... heh heh.
A common theme with my truck: someone had been here before me. Unfortunately they lost some of the ball bearings in the switch, and left out a support screw, and their solder job was less than acceptable. I found the 5/32" ball bearings at the local hardware store for pennies, and they worked perfectly. I resoldered the current path, too.
I cleaned the contacts with a Dremel tool and a wire brush, just burnishing the residue off the contacts and trying not to remove much material.