Anyone tried a rattle gun? (just kidding)
I haven't done anything with my adjusters except adjust them and after 13 winters and 140k miles, they're not seized. Just lucky I suppose. I wish I could offer some help, but the only thing I can think of is strip the fork down, seal the hole at the bottom of fork and pour diesel down the leg and leave for a week. You can see the adjuster at the bottom of the fork leg if you shine a light down there, so maybe you could attack it from the other side.
Either that or stick it in the oven for an hour and then bung it in the deep freeze.
I might be getting a bit Ichiban Moto there....
(in case you're not aware that the Americans have recently discovered a rich vein of irony)