Another advantage to top bar hive beekeeping. There's very little propolis in the tbh hive. And none on the ends of the top bars which is where I usually hold them. I can work several tbhs and come away with clean hand and hive equipment.
That's not the case with my lang hives. The bees pack propolis around the ends of the frames. And that's where I hold them, getting my fingers, hivetool and smoker covered in propolis.
The difference was very obvious when I worked both sets of hives today.
Thinking a tbh is a clean machine :> )