I met a man at a boat ramp this last summer. He was preparing his trot lines for a day's harvest. He had a piece of aluminum foil on each hook, and was spraying them with WD-40.
I was watching him, and asked him, "Do you really catch fish with that?"
His reply, "Yep. I've been doing this for the last 10 years or so. I have full lines almost every time I run them!"
"Been supporting my family this way for the last 6 or so of them years."
WD-40 might not be SOLD as a fish attractant. It definitely DOESN'T have any fish oil in it. But according to that man ... it's definitely a scent the fish are attracted to. They might be hitting the flashing piece of foil ... but they're drawn in by the WD-40.