Nick Evans wrote (see)

 If it's stuck down you won't be able to get it apart easily/safely. They go off with a massive bang and fire the air sleeve across the room, as the 'stuck down-ness' is massive amounts of air in the non adjustable negative air chamber.

Nick its not a massive amount of air just more than is in the positive side, pair of gloves and wrap the shock in a ragit does go pop only danger from it is it pulls a few threads off the body/can.

Cause of stuck down I;'ve rectified has been clogged seals with hardened grease used to assemble the wipers, since then I've just used fluid to assemble.

It's not a problem we've really encountered in ages, had one the other day, but we just throw them at Spesh now, or get one of the warranty bods to come and sort it!