[Dick Linn]

WD-40 is not a very good lube. It is primarily Stoddard Solvent/paint thinner, which evaporates. What's left does gunk up. It does make a good grease cutter.

For light lubrication, air tool oil isn't bad. It should have rust-preventative additives.

My recent favorite is Fluid Film. While primarily intended as a rust preventative, it does a decent job of penetrating and lubricating, doesn't dry out and is somewhat waxy. It contains Lanolin. Some use it on bike chains. I spritz it on battery terminals to prevent corrosion.