WD-40 is petr. based and I've heard it is best not to get it on mono. As far as scent it won't hurt a thing. Bass fisherman used to spray it on rubber worms as an attractant (ancient Chinese secret)! By the way if you dip hooks, swivels, etc. in olive oil when you are done with them it puts a coating on them and keeps the rust off. You can keep some in a jar and dip your good hooks before you put them back in your box or bucket.