Snap traps are the way to go. get them down fast though.....honestly, have a look at my profile pics and you'll see the damage they can do. Over the past two weeks, we have had water coming thru our ceiling about 8 times because they have been chewing our water pipes cue loads of money spent on plumbers, a £700 ceiling repair, time spent with no water and no heating. Honestly get on top of it as soon as you can.
The plug ins don't work because the mouse starts to get used to it and it becomes part of their environment, plus the sonic sound doesn't penetrate walls and ceilings. Rentokil told me he'd seen mice and rats running right past them (we had already wasted £20 on these)
Humane traps, yeah, they are alright but you have to keep checking them and then drive the mouse away at least 2 miles because they are fantastic at finding their way back to your cosy kitchen. They are ok for maybe one or two mice but who can tell how many you might have?
Get the wooden traps from B&Q, they are baited with scent and work like a dream. You just double bag them and throw the whole thing away after it is used.
The plastic ones are ok if you don't mind physically getting the mouse out of it and resetting the trap.
Are they coming out from under your cooker?
You have to get the mice under control before they start to breed.