Tri-Flow® oil is another great recommendation from Frank Ford (Frets.com). It is great for oiling tuning machines, roller nuts, or any other moving part on a guitar. Tri-Flow contains Teflon® and won't gunk up like WD40 or similar products. It comes with a long tube applicator that allows access to just about anything needing lubrication. Formulated solvents soften and remove dirt and contaminants, while special additives displace moisture and prevent rust and corrosion.
The Tri-Flow® Superior Dry Lubricant is an elite formula specially created for dry and dusty conditions. The drip bottle application, with a convenient straw, allows for deep penetration in hard to reach moving parts. Featuring paraffin wax and high-grade petroleum oil to allow the lube to go on wet, but then set up in a dry, "wax-like"' film so it will not attract or absorb grit and grime.