best way to remove rusted rear coils

[bbowser]

I'm tearing apart my 67 shortstep and gotten down to the frame/trailing arms. The spring retainers on the coils are rusted solid, top and bottom. I've soaked them for days now with PB blaster, but no luck. I intend to replace the springs/retainers so i don't care about trashing them, but I do want to re-use the trailing arms. Any ideas on the best way to proceed? Thanks in advance.