The Gerber Paul 2 disassembles very easily. The collar around the button lock serves as a locking ring that holds the axial lock/blade pivot in place. There are only 4 pieces to the assembly and they go back together without difficulty (there's just one spring and it's a reasonable size).
Wash the parts, put a little oil on them, and reassemble. Maybe put a little lock-tite (not the permanent kind) on the threads when you screw the collar back in place.