EZ,you are right. But this is setting straight some misinformation.
I did some research.
One of the first uses for WD-40 was 1958,it was used to prevent corrosion in Atlas Missiles.
15+% Mineral oil (light lubricating oil)
Slopemo,I assume what is in parenthesis is your own supplemental comment.
The drug store mineral oil would be alight oil,but 140 weight gear oil is also "mineral oil"
The writeup I found actually said "hydrogenated heavy mineral oil"
That "hydrogenated" thing is what they do to vegetable oil to make Crisco.
It makes oil grease-like.
And,yes,it is suspended in a volatile petroleum distillate.This article explained the trade name of the solvent used was Varsol.
Interesting side note: The owner/operator manual for my 1941 vintage South Bend Heavy 10 lathe suggested a formula to slush the machine with for rust prevention during shipping or storage.
It was petroleum jelly (Vaseline) dissolved in Naptha.I don't know,is Vaseline hydrogenated mineral oil?
Naptha is in the general class of petroleum distillates like mineral spirits and Stoddard Solvent.
The used to use it to dry clean clothes. Dry cleaning businesses used to burn down a lot. Naptha is pretty much Coleman fuel.
I would guess Vaseline (or RIG) could be put in a petroleum distillate of your choice just to facilitate application.
But beware flammability.