Sometimes when unloading filament when the plunger starts backing the filament out I've seen something happens and the filament does not move. When this happens switch to load mode and push the filament in a bit and then switch back to unload. more often than not the hot filament will actually pop out before the plunger starts moving.
I should mention that this is for the makerbot Mk7/8 extruder. I have no idea how it works with something like a wades extruder.
PS. This evening at MakeSLC. See you there.