Since the bleeder screw is at the highest point of the wheel cylinder, there's no practical way to do a good bleeding job if they're siezed up. I have freed up bleeders by totally dismantling the wheel cylinder, and heating the bleeder red hot with a torch. By the time you do that, there's enough labor time, plus the price of a rebuild kit, that it's more practical to just replace the cylinder. Is it worth betting your life on the cost of a few brake parts?

I've gotten very cautious in my old age! The very best brake work I can do is just barely good enough!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!