Couple things I've found trapping rats.........
1. a trap that has caught one and it leaves blood on the trap out traps other traps without blood on them.
2. the absolute best bait I ever had success with was lasagna. Two at once....and multiples in a couple hours. Like they didn't care if they got caught.
3. put trap under a half box like a carton used for can goods, pop, etc. Cut out doorway on one side. make sure tall enough for trap to work, although the plastic teethed push opens work well under a box. The box creates a dark space and they feel more comfortable eating. Perhaps the darkness tends to suppress the looks of the trap...who knows.
For what it's worth..........
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"By the time you realize your father was a smart man, you have a teenager telling you just how stupid you are."