1 Place the cotton balls in areas where mice are likely to enter your house, by doorways or heat vents, etc. 2  Another helpful deterrent is to grow peppermint plants near the entryways. 3  You can use the mint in cooking as well as it serving a deterrent purpose.
Nov 12, 2015. 20 kilometers (12 miles) for a 1 milliwatt beam. Laser light can travel 20 kilometers (12 miles) per-milliwatt that is contained within the laser.
The 5-milliwatt laser is powered by two AAA batteries and emits an intense, narrow beam of light at a wavelength of 532 nanometers. At night the beam is visible for hundreds or even thousands of meters, depending on sky conditions. Devices like this can be purchased for less than $20 from many sources.