I've been told by many gun buffs that WD-40 tends to attract and hold water, promoting corrosion if used for long-term storage..
The WD-40 website doesn't seem to agree - they claim that it prevents corrosion. Maybe the difference lies in using it for long-term storage vs. removing some water today.
I stopped using it when I found a thumbprint rusted into some blueing that had been "protected" with WD-40.
I've heard people who were positive on both sides of the WD-40 question.
It does tend to get thick and gummy and dirty even more than a thin layer of real oil does.
Now I only use WD-40 to break up rust, unfreeze a bolt, or displace water ... then I wipe it off, clean with a solvent, and relace it with real oil or silicon-based grease. I don't know what I'll do when my tube of RIG runs empty - it isn't made any more.
Some people suggest using Johnson Wax to put a hard, slick, rust-proof coating on metal. However, on a garden tool, it would be abraded opff rather quickly in use.
I love the idea of a bucket of sand plus oil, but get the metal clean (and maybe dry) before plunging it or you'll fill the oil with dirt and water.
