Wanhao I3 - Threaded Rods Vs Smooth Rods Lubrication

Ok, so I know to use Super Lube for all the smooth rods in my Wanhao i3, but I am not sure what to do for the threaded rods. I noticed that the threaded rods already have some grease pooled up on the threaded hole that they go it on the X-Axis assembly, so I am not sure if I should use lube or grease since they seem to have some with grease. I was told that grease is not good to use for anything with bearings as they can gunk them up, but I don't believe aonything on the Z-Axis uses bearings, just the Y and X axis. But, I was also told that typically the threaded rods need something more viscous than standard oil/lube to perform better.

Can anyone here who is familiar with how the Wanhao i3's threaded rods work offer some advice on this?