I could share about the piece of raw meat on a black eye, but I don't think it works any better than an ice pack and probably isn't what you mean... so I'll share this one...
If you ever loose a brake line, you can take a 6 penny nail with a flat head, insert it into a fitting and tighten back down and that will isolate that brake from the system... you drive with 3 functional brakes to get you to a place to do a real fix... did this 3 years ago to a 62 Chevy that had a single master cylinder... as we were getting ready to leave the parking lot, he hit the brakes and nothing!. We found the leak, did just like described, he drove the rest of the 60 miles to our destination and the next day had it repaired.
