ok before doing ANY work on this shaft do two things.
First. LOCK the steering column AND the car.
Second diconect battery.
reasons
If you discountct it and the column is not locked the steering wheel can spin as much as it wants. Best case senerio is breaking a $100 PITA to install conact plate that you must dis-assemble the entire stering column to do.
Worst case? All that plus a dash and windshield when the air bags go off
So lock steering wheel then lock car so no one moves wheel.
After that just remove the top bolt(like the bottom one) and remove the shaft. clean it up, paint it and put it back in

make SURE to reinstall bolts.
Good luck!