This is just my way- I add scent oil to the bag when I bag baits to 1, scent, of course...after a few days or a week or so, the oil is just about gone...the baits have absorbed it, and are now well scented (fish have keen sense of smell). 2, the oil helps the baits settle into the bag which reduces post-bag cure-curling (plastic changes over time, even a 7-day cure won't ensure perfect baits) and is just more Right for the baits to have settled in and aren't balled up.
Sometimes, if I want to, and I want be baits to smell strong, I'll add 10-20 more drops of scent oil after they've absorbed the initial dose, work the scent through the baits and settle them back into the bag...done. Personally, I like a dry bait, I don't like my baits to be slippery when I'm fishing, because that's more I have to wipe off my hands, more I could have on my hands when I need to be concentrating on the rod. The baits will last a L-O-O-O-N-G time dry in the bag, without scent oil or worm oil. A dry bait is easier to handle when rigging it, and my fingers aren't oiled afterwards, so I can get after 'em.
So it is said, the scent oil does not have to be "oily" on the bait for the fish to smell it. Once the baits absorb the oil, the bait is better scented than if the oil was just ON the bait, and the bait will remain scented longer after it absorbs the scent oil...the oil won't just wash off.
This is just me, though.
