Easy little trick for spinning ball joint studs

I was buttoning up the steering knuckle on a Jeep this evening, and the upper ball joint stud would spin after the castle nut got so far onto the threads. I thought some lubrication might persuade it to thread the rest of the way without influencing the ball joint stud. Long story short, a tad bit of ATF on the threads of both the stud and the nut helped me get it tight and get a cotter pin through. Not sure if anyone else has done this, but it was a quick and easy solution for me tonight.