water leak in hot water line
Sometimes draining just a few inches of water from the tank will provide enough relief in pressure to stop the dripping, if it is indeed siphoning back from the tank.  It's also possible that you just need to wait a bit longer for all the water to drip out.  Opening all the other faucet valves and flushing the toilets with the water off will also help drain the system.

I would avoid the bread if you can, though it will flush though the pipes OK, it will gum up all your aerators and valves.

If you do need to work on a pipe with water in, they sell Pipe Freezing kits which you apply upstream of the work area. These will give you 15-30min to work on the pipe while the ice block you created melts.