I saw a video of a woman who cut open a tube of fluoridated toothpaste, also cutting the end off, and put it in her attic. She stated that for 3 months she had no mice. When they began to appear again, she climbed the ladder and sure enough, the toothpaste was gone. (there were no mice bodies to be seen). She replaced the tube.
The toothpaste with fluoride is poison. I do not know how it works to get rid of the mice, or how it kills them, but apparently it works and they love the taste.