alt Hacker NewsBy Oxford English Dictionary literal definition, not all lubricants are fluids.
Etiquette is a mere lubricant of the order of society.
Fine music‥has a sensible effect in‥animating and as it were, lubricating my inventive faculty.
Lube also used for cash - greasing palms, etc.
Using the a non-lube to lubricate is still metaphorical.
But, I just ignore the word literally and english still works just fine