You can always undertake this as a science fair project. Start with two small pieces of metal mesh. Ensure the upper piece of mesh has openings greater than 10mm square. Isolate the two pieces electrically with some nylon standoffs or other dielectric material. From an old TV, remove the horizontal output or high voltage tripler assembly. Be careful, as the second anode socket which connects to the picture tube has a voltage potential exceeding 20kV. Connect the two sides of the HV assembly to the two screens assembled in step 1. Bait with peanut butter, and wait. When you hear
BVVVVVVVT you've proven the effectiveness of your own homemade mouse-zapper. Be certain to de-energize the circuit before removing crisp remains.
The preceding is for humor purposes only. Do not attempt. You could shoot your eye out.