Serious question Will, you've not got any boxes of wine lying around that you've not checked or anything else munch throughable that contains alcohol?
Never seen that before and I'd say I've now got quite a lot of experience in mouse related matters and have seen them in many differing states, from not at all dead to almost dead to positively splattered.
Superglued hardish cheese is the best thing I've found, even if the trap is not set sensitively enough to go off immediately, if they've got to gnaw at the bait then it is only a matter of time before they cop it. What traps you on? I've had best results with the little nipper wooden jobs, they are tweakable to make them mega sensitive, take a bit of emery cloth to the top of the pin and squidge the hairpin bit with some pliers, makes them a PITA to set but they are lethal. Never fails
Other than having to listen to the dude that reads the sport on the BBC Scottish news, I struggle to think of anything more annoying than giving a mouse a free meal so I've spent quite a bit of time looking at this shit
Most of the plastic or metal traps are crap. Those vegetarian traps that allow you to 'capture' and relocate the cute little mousey are quite good but it becomes wearing putting the live mouse into a box and taking it outside to humanely dispatch it, but it is the best way to get them all IMO and you always know they've had a quick death.
Cheers
Ben