A live trap? What the hell you gonna do, relocate it like the hippies do with prairie dogs?
If you want to catch it, use a big Victor snap trap. For bait, peanut butter melted into a cotton ball wired to the pan of the trap works great. If you use just peanut butter the S.O.B.s will just lick it off. If you don't tie the trap to something there is a good chance that they will take it if it gets sprung without killing the rat.
I have tried Irish Spring soap, all natural sachets, and lots of other "home remedies" only to find that I was just giving the little mofos nesting material. I won't use poison for quite a few reasons.
When I was a kid, we had squirrels getting into the house. One day while my mom and sisters were away my dad and I went through the whole house moving everything around looking to kill them with a .22 rifle loaded with birdshot. I remember him shooting one and the mess it made.