Be sure to pull the battery wire before you pull the instrument cluster - lest you short the ammeter lugs against the chassis and have free fireworks in the dash.
You can use a .22 cal bronze brush, in a drill, to clean your fuse contacts on an FJ40. I heartily agree with removing each fuse, being sure the metal caps aren't loose, and cleaning the fuse sockets, tightening them if necessary by bending the contacts.
Colo Springs, CO
'78 FJ40, '89 FJ62, '98 4Runner