There are proper tools for the job...a bushing driver...
I'd resist the temptation to use a chisel and hammer,though it might work,but you risk boogering up the soft aluminum housing..you might be able to saw a slot in the old bushing with a hacksaw blade carefully,just deep enough not to saw into the housing,then it will be easy to collapse it and remove it..
I used that method to remove the "shell" left behind on a suspention bushing (like leaf spring bushings) on a Honda today--it had those sucky bushings that had steel sleeves in them that always seize to the bolt and the bolts must be sawed ir ground off ,to get the rear struts off,then the rubber centers melted or punched out,then you can saw a slit in the outer shells and remove them without damaging the control arm...I used a long threaded bolt and two sockets to draw the new bushings in..