For those who do not have purpose built ESD protection, I suggest the following:
Connect alligator clips to one end of two 4' lowish gauge flexible wires (stranded 18GA or less). Bare the unclipped ends and screw them down to something that's grounded (say a handy computer case).
Clip one to your watch strap so the clip is touching your wrist. Touch the other to your PTW before you begin disassembling it. Try to hit some place in the mag well where there's a spot where your paint has worn off as you want to hit bare metal instead of a chunk of insulative coating.
This arrangement will continuously dissapate ES that you build up while you work and initially bring your PTW down to ground plane before you start digging around in it's brains.
Want nearly free GBB gas?