Rust-frozen brake bleeder screws

Since I grew up in the rust-belt, I’ve had problems in the past with frozen brake bleeder screws, my MH (which used to live in New York) is no exception. The brakes currently work well and have nice thick pads, but since overall the MH is a monument to neglect, I’d like to replace all the flexible lines and replace the DOT 3 brake fluid with DOT 5.1 high temp brake fluid. In the past when I snapped a bleeder screw I’d bleed the brake cylinder by loosening the brake line at the wheel cylinder and bleed it there. Not the best method, but it normally worked reasonably well. So far I’ve been heating the area around the screw with a butane torch (but not very much for obvious reasons) and then I’ll squirt penetrating oil on it. Other than this preliminary skirmish, I haven’t seriously attacked the stuck bleeder screws yet. Does anyone, particularly you rust-belt denizens, know of any “tricks” to loosening rust frozen bleeder screws without breaking them?

Thanks in advance for any help and insight all y’all can give me.

Steve