What is the very best bait to use for rat traps? Don't say peanut butter b/c I already tried it, no bites.?

There are several rats in my house. I started using the snap traps. I caught a few like this but can't stand dealing with the bloody mess. ...so now I use an electronic zapper trap.

The baits I've tried are: dry roasted peanuts, Jif peanut butter, store brand peanut butter, dog kibble, dog biscuit, organic fresh mini sweet peppers, dried tart cherries, raisins, graham cracker, honey wheat bread, baby carrots, Trader Joe's Pecan Pralines.

The bait I started with on the snap traps was peanut butter. No rats caught after several days. The next bait I tried was dried cherries. They didn't go near the trap until I took out the sack of flour they had been feeding on and set it right beside the trap in such a way that the rat had to step on the trigger to get to the flour. 24 hours later, dead rat. Next time I did the same thing but no rat until I switched to the red sweet peppers. Less than 24 hours, dead rat. This was when I switched to the zapper trap. The dog kibble didn't work. The dog biscuit only worked for 3 very small rats, no adult would go in. The mini sweet peppers did work as long as they were the red ones, will NOT go near any other color. 2 days ago I set the trap up with dried cherries, so far no dead rats.

I'm very tempted to put a bit of flour inside this trap but haven't for fear of the flour getting under the floor plate which will stop the trap from working. Remember, this is a zapper trap...not supposed to use goopy bait (PB) or powdery bait (flour).

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