WD40 is great for dealing with things that are rusted in place, which is what it’s supposed to be used for. It’s just that it’s not a great lubricating oil, and people often recommend it for use as that. Too thin and leaves a waxy residue to repel more water from rusting the surface, which you often don’t want in things that you’re lubricating.
One of the few things WD40 is actually good for.
WD40 is great for dealing with things that are rusted in place, which is what it’s supposed to be used for. It’s just that it’s not a great lubricating oil, and people often recommend it for use as that. Too thin and leaves a waxy residue to repel more water from rusting the surface, which you often don’t want in things that you’re lubricating.