Disassembling shocks

[jrd-28]

I've got a pair of shocks which came off my '28. They're pretty well rusted together, what a surprise.

To disassemble, it looks like I need to clamp the base in a vice, grab the outer cover with a pipe wrench, and unscrew it. Is there any particular trick there? Is it ok to heat them up? I haven't been able to budge the first one I tried with a 2 foot long wrench.

I guess the corrolary question is if they're so badly rusted that I can't get them open without heat, does that mean they're junk?

Thanks for any wisdom.