So, we've got mice between the floorboards.
Specifically in the ceiling of my room and the rooms above.
What can I do?

We had mice, and managed to kill four in a week using strategically placed traps laden with peanut butter.

You really don't want them to die between the ceiling and floor boards though, you would probably have problems with flies and all sorts. Best bet is to find where they are getting access and lay traps in that area - they will come out of the floorboards to eat etc, so ideally you want to lay plenty of traps there and catch the little scroungers. When you know they're all gone you can block it up.

+1.

We've had huge problems with mice. I've sealed my room. There were gaps beneath the power socket behind the desk, and holes around the radiator pipes.

You basically need to find out where they are coming from. We found one hole by a pipe in the garage near the front of the garage. We found another one in the corner of the front door step! We blocked all ventilation holes with bricks. We don't know where the other access areas are and suspect one in the kitchen. But it'd mean ripping the kitchen units apart!

Traps are going to be better than poison. I didn't bother filing down the little metal pin trigger thing, but put it on the edge, so it's more sensitive. Mice are clever and I've heard a trap go off, but no mouse and no bait! Using peanut butter means they can't scoop off with the food. Lay wooden traps in each room, so you'll know the problem areas. The front rooms of the house for us remained clear. My room was involved because that's where the boiler used to be, so lots of old pipes/tunnels, and it's closest to the stairs. The downstairs kitchen was the other main problem area.

Needless to say, be OCD about leaving out food, especially uncovered. We would wash, dry and put away all dishes etc rather than risk mice licking them!

Works every time.

Be f***ing careful about Leptospirosis!

Clean everything before everytime you use it. It's a PITA but better than Weil's Disease.

Take off and nuke the site from orbit, it's the only way to be sure.

Yup.

Worked for Ripley - ish

Apparently dark chocolate is also good for use on traps.

I strongly recommend keeping cereal etc in sealable plastic containers, instead of keeping them in the cardboard boxes. I also echo what Rusty has said - clean *everything* before use, Mice are dirty buggers.

If you don't fancy tackling the problem yourself, your local authority's pest control department will come out for a mere £50 and lay traps, poison etc.

They can get through gaps as small as a couple of cms. Plug the gaps and you're good.

Ok - we had mice in the kitchen a while back, raiding the bin. Now we've got a food caddy for recycling that's kept well shut and out of the way, we've not seen any since. Trapped quite a few, and then nothing. No droppings in the cupboard under the sink, nada.

Then now we've had the cold snap, they've gotten in under the floor boards. As I write this, I can hear one grinding away at something, scratching about right above my head.

So they're not in the body of the house, they're just under the floorboards between my room and my parents. No signs of any rodents in the kitchen area.

Where and how they've gotten in, I have no clue. Our house is on a slight hill, so I'm ground level, but the rest of the house is above me on a single level, if you follow me. I'll have a look around tomorrow and see if there's anything obvious, but as the area they're inhabiting is approx. 8 ft off the floor, and nowhere need any food sources, I'm a little stumped. Unless they've got in via the back of the house somewhere, which is ground level...
The other problem is that we need them gone, not just dead. I don't fancy the smell of rotting mouse in my bedroom.

Right, call my man Keith on 07517 788 248. We use him at work for absolutely everything and he knows his stuff. I know he covers Plymouth as well as Cornwall, so he might be prepared to stretch to you if you tell him I sent you.

Folks have just taken a contract out with Rentokil... traps have been laid, wheels are in motion. The chap was quite amusing, in a way, as he's ex-army and he's clearly just fighting a different war now. A war on rodents.
We've been told to expect slightly more activity for the moment. And yes, as if on cue, I can hear one the little blighters scurrying about above my head.

Be careful the mice might respond....

Danger Mouse - still awesome

As a kid, I found the prospect of DangerMouse cool - the character, the car etc. But I found the plot boring. Maybe it was too much dialogue and not enough action?