As one who has brought back to life a few apparently comatose`d if not dead cars, I found the easiest method for me to release a "stuck clutch" was to get the rear axle up on STRONG axle stands...... After the engine has been warmed up to close to normal running temp, just put it in gear, bring the speed up and with some careful heel and toeing, hold the clutch down and  hit the brakes hard, this method has till now always worked though on occasion more than one attempt has been found necessary.

To polish the rust off the flywheel, when back on the deck I just sit at the clutches "point of contact" for a short time thus very lightly polishing the faces by slipping the clutch. It is possible to expand on this method by jamming the clutch actuating mechanism in order to free your feet from the necessity to heel and toe should such dance steps be found difficult to those born with feet unsuitable to such intricacies
within the confines of a Morgan footwell.

It may be worth while to note that "my method" is best not tried in an enclosed space, due to the fume implications, and perhaps it is wise not to be pointing at anything "hard" should you use an unsuitable method of keeping the rear wheels free of the deck......Enough said (typed) ?