I bought an electric trap at Lowe’s or Home Depot. It uses 4 D batteries. Smear some peanut butter on the bait end, turn it on, and wait for the rat to get electrocuted. Sometimes I have to place it up against a wall so they don’t get the PB without going inside the electrocution tube, but once I do that I can continue getting them until I have to replace the batteries.
Is disposal of the rat carcass a problem?
The electrocution traps work well BUT you have to check on them frequently as a week-old corpse begins to fuse with the trap and its dreck to unglue them. I have had to toss two of them with stuck rats so that defeats the approach. If they add a bluetooth sensor so you know when they discharge that would be great.