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

I just had to do this on some Kelsey Hayes calipers. I just plan to replace the bleeder in the beginning. So, don’t use a wrench it’ll just round the bleeder off. Start with vise grips, a big pair, clamped TIGHT. Heat the caliper around the bleeder, hot but not red, use lots of penetrating oil. The Kroil mentioned above works best for me. Once hot and wet (see what I did there) turn the Vice grips both directions back and forth, tight first then loose. Keep heating and spraying and tugging back and forth. Sometimes a few taps with a small hammer on the Vice grips helps. They will come loose, or break off. Good luck.