A team at Drexel University in Philly conducted side-by-side comparison tests of vegetable oil mixtures, WD-40 and automatic transmission fluid, and found that a mixture of vegetable oil with 10 percent acetone works as well to free rusted bolts as WD-40. And it costs about one-tenth of the price. Add more acetone, up to 30 percent, and the mixture works even better than WD-40 and still costs about one quarter the price.
Acetone, by the way is the active ingredient in nail polish remover and some paint thinners, and DIY mixtures with transmission fluid are sometimes used as a penetrating oil.
[Images by (left to right) cottonseedoil, dchou0123 and ATWJ - mhoey.eu / Flickr]
Step 1: Tested & approved
Vegetable oil with five percent acetone works. Increasing the acetone to 10 percent or up to 30 percent boosts performance. At higher concentrations, you can free the seized bolt using less than half of the force that it takes with WD-40.
The bottom line is that vegetable oil with 10 percent acetone is more effective at freeing seized bolts than WD-40, it's as effective as ATF and acetone, and it is more widely available in rural developing areas and kinder to the planet both in manufacture and disposal.
This might be useful in anyone's garage, but we're hoping that it's especially helpful in rural developing areas where commercial lubricating sprays can be expensive and vegetable oils are easy to find and even possible to make.
The tables show a cost analysis and a comparison of the force needed to remove a seized bolt (courtesy of the Drexel team).