Just a thought here for folks that are having issues taking the switch ...'y apart. You could drill a small (smaller than you would need to tap threads) and gently drive a small nail (finishing nail maybe) into the hole. Then you would at least have something more to hang onto with pliers when trying to turn the bottom button. Then mod as usual.
I was one of the lucky ones. Mine came right apart but I have another #19 coming from Exhale next week so I may be in the same boat as some of you then.
I think I read somewhere on here, someone tried doing that and cracked the magnet.
I have another magnet that is a little too big for that cup. I've never tried sanding/shaping a magnet - so I'm not sure I'll be able to utilize it.