@TheDudeThe Mean Green Cleaner you are using is a good degreaser, but what you need is a penetrating oil to get down into the threads of the bale and get rid of the rust. Do you have anything like PB Blaster handy? Give it a good spray and allow it to soak for 5 min. Next use a wire brush to scrub at the nut as best as possible to help loosen any rust at the surface. Re-spray with a healthy shot of the penetrating oil almost using it to flush away the mess left by the wire brush and then allow it to sit for at least an hour - longer if you're patient
Oh and if possible use a 6-sided socket as opposed to a wrench or a 12-sided as you will maximize your torque on the nut without stripping the corners off.
Good Luck, and keep us posted!