I have a small PCB repair I need to make. I am reading that wire-warp is a suitable option. I don't have any wire wrap, but I do have tons of cat5 and cat6 solid core wire. I was thinking about gutting one of those and using an individual strand from as a jumper. Is this a bad idea? Or is this a case of if it works then it is a good idea?
You can, its really great for breadboard wire. I used to use Ethernet or phone as my primary way to prototype (now I only solder).
A better way is to use the standard "blue wire" 30AWG for jumper connections, its smaller so it's easier to attach to most SMT pins.
There are some caveats with solid core ethernet wire though, The main problem is strain relief and breakage. As with any wire, stripping can nick the wire, and the wire breaks after moving. This is especially a problem if the wire is causing intermittent connections, it can be hard to track down.
So be careful not to nick the wire, and if you can, provide strain relief with tape or soldering. Don't move the wire after it is placed.
(you should also not use solid core ethernet from the wall to the computer, if it's stepped on it breaks, and if it's moved too much it breaks, use stranded instead)