Stand beside the Jeep and open the door, and swing it open is you can visualize a 90 deg angle from its closed position...,.go too far and the door will hit the body call this 180 degs. The purpose of doing this is to allow access from both sides (the inside and outside of the door)

I would place the floor jack bellow the hindge point of the door, meaning bellow (due South) of the last hinge. Its this point were pressure is needed, don't place the jack at the opposite end, (due South of the door handle) pressure he will produce an unwanted angle as you push the door up.

A block of wood and a rag (as per Beserkur above post) will help displace the force and ensure you do not scratch your paint.

Again, get yourself set up, and once the floor jack is in place, try small amounts of lift at a time, too much and the door will "POP" off which casue you harm or damage the door. You won't need much pressure, the floor jack will provide plenty of leverage.

Good luck

 

Wood man don't forget to put a pc of wood between the jack and the rag Its jack, wood, rag, door.

 

ok...so Im going to have to go to my buddys shop and use his professional jack obviously. The only one I have is the cheap turn ones that come with your cars lol. I have the 2x4s and the rags. Ill see if I can get ahold of him and let u know how it goes. Im going to grab some lithium grease too, so I can grease the hinges before I put them back in...

 

try Moovit by Lloyds chemicals....environmentally friendly too!