Any tricks to removing a stuck/stubborn/rusted-in place bleeder?

Are the calipers Aluminum?
I'm 99% certain they are not (aluminum).

And I want to say they are single piston, but I'm not absolutely positive on that. Pretty sure I don't have any pictures of the brakes, as I stopped taking pictures (i.e., stopped "documenting") once I found the cracked frame. After that was repaired it was "all hands on deck" to get the car running, so I didn't take too many pictures.

(Hmmmm. I wonder if Bazza would know....)