Just want to add another method I've used:
I just replaced all the bushings in the front end of my Durango, and found an easy way to remove the old bushings while leaving the factory metal sleeve:
Heat it up with a propane torch - you're only heating enough to break the glue bond. Chuck up a drill bit in a cordless drill, drill down through the bushing real near the sleeve, and then reverse the drill direction. When you pull the trigger on the drill, you will have to keep downward pressure, because the bit will want to come back out of the bushing. If you do it right, the bushing will literally walk itself out of the shell all on its own, like magic.
Trust me, this works. I did this to 8 control arm bushings and replaced them with Energy Suspension bushings, and it couldn't have been easier.