I know I'm late to the party but this is the easiest way I've found to remove bushings on a factory style open arm.
I start by drilling the rubber out to give me room to collapse the shell, no need to set the rubber on fire or anything like that. Drill 2 holes straight in, then drill an X between the 2 holes, this will help to clear the rubber out easily. Once the rubber is gone you can use a chisel and hammer, or air hammer if you have access to one. Pinch the shoulder of the shell in, then proceed to knock the shell in on itself in a straight line. This will cause the shell to shrink in circumference and loose it's grip on the arm to the point you can easily knock it out.
To reinstall I purchased 1" angle iron from the local hardware store (or you can use pipe, whatever you have handy). Measure the openings of all the a-arms I was working on and cut the angle iron to an average length of all of the measurements. Put 2 pieces in between the a-arms and used a hose clamp to hold them in place, then proceeded to press the new shell/bushing into place. I WAS pressing in the bushings without the hose clamp until 1 piece of angle shot out and pinged my thumb. Now the knuckle has a click to it that reminds me of all the stupid trophies I've earned over the years..
I have used sockets in the past as well, but angle iron and hose clamps are an upgrade.