I either use whatever is in my grease gun(almost exclusively Schaeffer 219) or I have some 16 gallon barrels of contaminated JT-6 Hi-temp that came from my previous employer. If I'm close to the barrels I'll scoop a little out and smear it on the ball. I mainly use the barrels for 5th wheel lube on the OTR trucks and apply it with a putty knife. It is contaminated with some water and wood dust but still works fine in exposed applications where it's going to get more junk stuck in it.