CrappieTom is correct stating that oils can be smelled in water. All of our scents are oil based for adding to hot plastic and used again for packaging them afterwards or adding to existing baits. I have had many, many trials on the water testing scents added to molded baits prior to molding and added afterwards. The cooked in scents displace the plastisol smell giving baits much more appeal. The scents added to baits after packaging them slowly permeate into the outer layer of plastic reducing even more plastisol smell. The oil will disperse ( when scent is added to packaged baits ) once a bait is casted into the water, but that is only the oily residue of what remained on the surface of the bait. I can't tell you how many times I've fished an area of a lake with handpoured baits using plain ( no scent added ) baits and then another with our scent(s) cooked in and added afterwards....the end result is scented baits outperform non scented baits 5/1. And again, this is an oil based product which some people say don't help?? It's quite clear that enhancing a plastic bait greatly improves your chances in achieving more hook-ups.
-Doug