I've done this method with Rack&Pinion Steering, so I don't know if it will work with the Jeep Recirculating Ball, but how I understand it workings it should work just the same.
Just like above, you disconnect the return line and run it to a bucket. But, let the reservoir run dry before capping it off. Put the front axle up on jackstands, so you can easily turn the wheel without power steering. Just turn the steering wheel lock to lock, the P/S box will pump the fluid thru the system and out the return line. No need to start the motor and risk doing damage from running dry or getting air in the system. I usually add a few ounces of fresh fluid and pump it thru the system to flush out every trace of old fluid. Then reconnect the lines and fill, while turning the wheel lock to lock to pump it thru and get all the air out. Start the car, run for a while, then check the fluid level and top off as necessary.
I'm going to try this in my XJ within the next couple of days, I'll let you know how it works out.
NOTE: Air in hydraulic systems can cause a HARDOVER, basically an air can get in one side of the piston/servo but not the other side, air bubbles stick a valve, etc, basically the piston could drive to full stroke uncommanded. That means its possible the steering wheel could spin to full lock in one direction with extreme speed and force.
So while you do this job, you should be careful, and watch out for this HARDOVER. If you happen to stick your arm between the spokes of the steering wheel to turn the ignition key or put you foot right up against a tire, and in the rare case the steering hards over, you break some bones.