DPs have been around a LONG time. Some of my first experiences with hem were the egg trap, and duffers DPs.
I bought a bunch of both in early 1990s and realized hers a tool for right place, right time.
Pic of coon I caught in...1992, in duffers DP prototype I bought from him at NE fur harvesters convention.
Tricks Ive learned over the years. Coon like eye appeal. Coon like things that smell like food. Coon like to eat. Coon are reachers and grabbers. Can grab with all four feet. Stake for an elephant, and gang set (more than one trap at each location).
Stick it right under their nose, i.e. right in middle of trail.
I use cheap dry cat food mixed with molasses and I only put enough right up to trigger, I don't fill up the trap. Others do and maybe i should but havent yet. A little good smelling coon lure on lip of trap like caverns moonshine, Blackies midnight coon lure, hawbakers coon lure, any lures like that work for me.
Pic of my stuff ready to go this year. I made 2.5 gallons of cat food mixed with other goodies. Molasses works, dry shelled corn works, fish works, fruity smelling stuff works too. Trap coon like trapping coon. Variety of baits is good but not always necessary. Variety of sets and traps have been more important for me.
I haven't had a such success with fish oil as attractor but still playing with it. I dont think it tastes as good to them so maybe as a trailing scent its better. When I ran a lot of pocket sets I used fish oil squirtrd around outside of slicked up pocket and it worked well at water sets. For some reason not quite as successful for me on land I do better with sets without it.
I use golf balls on top of DPs sometimes, and sometimes I dont. Works either way. If mice steal the bait use the golf ball.
Main thing is set on sign.
Also, DPs are not always most effective tool. Ive had them walk right by a pair of DPs only to end up in a 220 or 160 a little farther down same trail. DPs are great but like any coon set they have limits. Coon can be finicky at times. Ive had them work dirtholes with fish and loud coon lure and sometimes they walk right by and end up in a blind set 160 just down the same trail. Point is trap coon like trapping coon and DPs are just another tool you can use.
Ive learned long time ago and especially in later season colder weather coon to alway mix in a blind set or two also.
Fishy baits work in DPs but also attract other critters.
I have brown DPs, and some ive painted white. They all work. Set on sign. Have fun. Eye appeal though, and scent, and stick it right under their nose. Then dont be surprised if you check empty DPs from time to time but still see fresh or new tracks by your DPs. Throw in a blind set and take those coon.
Jim