I found that grease just collected dirt which adds to wear. From looking at my hitch head I don't think it looks like it has any wear and that with a alot of miles on it. ON my personal trailer with the Reese Dual cam i did use petroleum jelly on the bars but that was it.
1990 Jayco 250 Special
2008 Ram 5500 DRW 6.7, Cummins, Aisin auto
Holland/Binkley 5th wheel, Reese Dual Cam, and more
232,500 kms in 2013
200,000 kms in 2014
160,000 kms in 2015