I would for the following and you could too. Unused, you could mix it with a little gasoline, pour into a garden sprayer and give a rust treatment to the rocker panels, rear quarters, door drains, inner outer-fender welds and anywhere else you see access to potential rust areas. Catch drippings on old rags/paper and wash in a week. Otherwise, I'd donate to a waste oil burner for heat if one was in the area.
Also use to coat machine parts left out side that are perpetually exposed by "painting" on with a foam brush. Great rust preventative, but be careful of ground water exposure.