[Gearhead999]

The problem with heating the plugs is that the heat will cause the plug base to expand and be tighter in the threaded hole.

I would, and have many times, squirt a mixture of ATF and spirts [kerosene, etc] around each rusted plug. Do it for several days. If you want use PB Blaster instead.

Let it soak and keep reapplying it. They should work out. Loosen a little, then turn back in. Back and forth, use plenty of PB. Patience is a plus here.

If you want hit the base of the plug with refridgerant. It will freeze the plug base, which will shrink it, and aid the removal.