I know some people swear by WD40 as a fish attractant. Personally I don't buy it.
For one thing it's petroleum based. If you ever want to go trout fishing and not catch
anything get some gasoline or motor oil on your hands before you go. Fish will refuse to
hit a lure, and will quickly drop a mouthed baitfish when they pick up that scent. I learned
this the hard way decades ago. Secondly, being petroleum based is it really a good idea to
be using this stuff in the reservoirs which supply drinking water?
Anyway, I think that if WD40 has any value, it probably masks human and other scents. But
the same can be achieved with the numerous safe fish attractants and scents on the market.
But I do use WD40 sometimes when cleaning up my reels in the winter.
Ken