We've had some great success against our mouse problem recently, and I wanted to share what has worked for us.
I started with peppermint oil, which did drive the mice away, but we also noticed that peppermint oil has to be refreshed frequently otherwise they quickly return. Sometimes they even steal the once-peppermint scented cotten balls for nesting material. I've since added Bounce sheets and kill traps.
I don't like killing mice, but it is, bottom line, the best way to reduce the population. In just five days we've caught two mice and one mole between two traps. That doesn't seem like a lot of mice, but I suspect these were the main foragers for the colony. The mole mystifies us. We do have a mole problem in the yard, but we didn't expect to see one in the house. It actually survived, managing only to get a leg caught. Joe let it go near the well house.
The Bounce sheets work wonderfully at keeping the mice away. The box I bought was particularly "stinky" (i.e. extra fragrant -- why would anyone use this stuff on their clothes?), and I only noticed at home that it was ranked "4 out of 5" levels of fragrance. (You mean there's a Bounce sheet that is one level stinkier? Dear god.) Perfect for mice. Now my kitchen smells like Bounce.
I put Bounce sheets in non-food related areas -- the drawers with my candles (which the mice had been chewing), under the sink where they pass through on their way to other areas, the drawer with various kitchen appliance manuals and warranties, etc. I didn't want to use the artificially scented sheets near anything used for food, so I spritz with diluted peppermint oil where I have pots and pans, utensils, and food prep surfaces.
I've noticed a significant reduction in mouse droppings and other mouse evidence in all areas where they've been a problem in the past. I haven't found any mouse droppings at all in drawers that contain Bounce sheets or refreshed peppermint oil. Unprotected areas are places where we've put a trap -- we're trying to draw them out and attrack them to the food bait in the kill traps -- yet even these areas are showing only a stray mouse dropping or two. Wherever the mice are these days, it's not the kitchen.