Never use vasoline as it breaks down and also has a tendency to pick up dirt. I clean my lugs and t-rods and then apply a drop of 3 in 1 oil. I've never had a problem with t-rods backing out. WD40 is great for cleaning but it is not a lubricant.Jack:)
You're right...WD-40 is not used specifically as a lubricant...but it does have a small amount of penetrating oil in it....and I have never had a problem with "t-rods" backing out, either...but I think TMTM is asking mainly about lug screws, not t-rods.:Snow Flake: