> WD-40 works great for its intended purpose.

When I was a kid some family friends used WD40 on their joints - arthritic knees and such. Church friends, actually, which I mention only because stuff like that probably helped me reject the religion as readily as I did.

A web search for "WD40 arthritis" shows that there are still people doing this.

Maybe they think it'll work better since it penetrates deeper than vaseline.