what Driller said....use a large flat-blade screwdriver to remove the locking C-clip from the solenoid anchor, then rotate the solenoid 1/4 turn.
The pressured air will force the solenoid down and allow the air to escape. It'll startle you for .5 seconds, and within 2 seconds, the bag will suck up empty.
use a large socket - LARGE ENOUGH TO FIT OVER THE LOCKING TABS, but small enough to actually depress them. I used a brass hammer to knock the socket on to the tabs, then used a screwdriver through the socket's 3/8" or 1/2" square hole to press the bottom of the bag UP to release it from the LCA
then grasp the top of the air bag shoulder and rotate it. It will only turn about 1/3 turn and release from the two locking holes in the top. Compress it by hand and remove it.
HERE'S A LINK TO my whole "how to" remove air suspension on a Mark VIII.
http://www.cardomain.com/ride/850999/1994-lincoln-mark-viii/