Regarding margarine:
As an experiment, I baited 3 identical rat traps: One with peanut butter, one with regular butter, and one with margarine. They were all placed along the North side of my house out of the weather.
Peanut butter caught a rat every other day.
Regular butter caught a rat or two per week.
Margarine caught nothing over 3 months.
I even swapped the placement around and refreshed the bait, but the results were the same.
If rats won’t eat it, it’s not food.
*My* rat problems are pretty much over since I got a new cat...
Watch which foods flies and ants avoid on picnics and camping. They don’t like the highly processed junk foods.