You need to use stuff that stinks for catfish. I heard of some people that let stuff rot in a bucket for a week or so. It smells but they catch big fish.

WD40 probably helps. I guess its the oil. Maybe some motor oil would work better and stick better to the bait. Motor oil is thicker than WD40. I wonder if some grease you use in a grease gun would be even better? Maybe I will try it one weekend and report back.