https://www.engineeringforchange.org/news/2012/08/14/how_to_make_penetrating_oil.html
“Results
Vegetable oil with five percent acetone works as wells as automatic transmission fluid with five percent acetone (used ATF is sometimes substituted for penetrating oil in resource-poor areas). Increasing the acetone content to 10 to 30 percent boosts the mixture’s performance. At that concentration, you can free the seized bolt using less than half of the force that it takes with WD-40”
It’s funny how one does things thinking they are a bit odd and then finding it out in the general culture.
Since I often work with epoxies as primer and fixative, acetone is always in the shop. I have splashed some on seized bolts to carry the wd-40 in better thinking I was just being a crazy rogue.
It makes a great dryer for paint prep as well, similar to alcohol, it carries away water and oils due to it’s unique molecular structure. Where a bare metal piece may flash rust while drying, I rinse in acetone and dry so the water is removed faster.
I remember hearing about how well a 50-50 mix of ATF and acetone works better than even Kroil to free rusty fittings. http://www.garagejournal.com/forum/showthread.php?t=182271
I guess it doesn’t stay mixed very well, but those numbers are impressive.
One of the guys here uses Oil of Wintergreen, aka methyl salicylate.