His website says "Shooting lighter fluid or powered graphite into the shutter is a momentary solution… for a few days! The shutter must be partially disassembled and the parts flushed. I do it electronically with a rather powerful medium that, unlike lighter fluid, does not leave any residue… but the fumes sure get my wife a tad upset!!"
I'm guessing that he uses an ultrasonic jewelry cleaner. There are specially made chemicals for those ultrasonic cleaning machines.