I used to be squeamish when it came to mouse traps but not anymore. I tried D-con, and had the joy of trying to locate the dead mice by smell.
(I think it’s coming from under that stove, ewwwwww)
Now I just set em and wait for the snap. BTW it’s better to get the traps and empty them when they are as fresh as possible. They don’t seem quite so icky that way. You can pretend they are just sleeping.
Dynamite.
(WHEE! Gonna blow um up REAL GOOD!) 
Oh man, Missy2U…your SO sounds like my dad. He is MR. MOUSE KILLER. Couple of funny stories, since I have no real advice to share that hasn’t been already given…
Story #1.
Setting: My childhood home in Maryland.
We occassionally got mice in our house…we’d notice mouse poop in the cellar, and that someone had eaten through the bag of peanuts we had stored down there. So my dad declares war on the damn things. Well, he got most of them with the spring traps. But one escaped, and managed to get UPSTAIRS. After lots of hilarity that I don’t remember, my dad manages to trap the mouse in the hall closet. At the time, we still had our dog, Gretel. Gretel was a terrier…she should go after the mouse, right? Lord knows she went after the moles, rabbits, and squirrels in our backyard… NOPE. Dog is NOT interested in going in the closet to get the mouse. So my dad goes into the kitchen and gets some pepperoni. He then proceeds to THROW IT INTO THE CLOSET. This was supposed to send the dog running after it, whereupon she’d find the mouse and kill it. Of course, this didn’t happen, and my mother and I were laughing hysterically. My dad stalked off after a bit, growling at all of us. IIRC, the mouse was found in a couple of days, still in the closet, dead.
Story #2.
Setting: My parent’s apartment in Memphis.
It was one of my last visits before my parents moved into their house. I knew they’d been having some problems with mice…there was a trap in my bedroom, for crying out loud. Well, I went to bed one night…I tend to bea semi-light sleeper, so I put earplugs in. I slept through the ensuing mess, which I got to hear the next day.
My dad had seen mice in the kitchen, so he apparently set out two new traps before he went to bed. He was in bed for a while, then heard “SNAP!” He went out to the kitchen to get the mouse and dispose of it. Well, the trap hadn’t snapped on the mouse’s neck, killing it. It had snapped on his TAIL. When my dad turned on the light, the mouse panicked, and tried to run under the stove. While normally the mouse could fit under the stove, with the trap on, it couldn’t. So my dad gets a broom, and starts trying to kill the mouse by hitting it with the broom. This didn’t work. My mom comes out and starts laughing at him. He gets mad and starts yelling “This broom is terrible at killing mice!” It deteriorated from there.
So Missy…I feel yer pain.
Missy, whatever you find that works, let me know. We just a quired a small, furry rodent of our own. However, my usually-afraid-of-everything-but-her-own-shadow black Lab has decided that she is the Mouse Hunter so I’m hoping that she eats it! But just in case…
I can’t back up Zenster enough here.
Warfarin
They eat it. It screws up their blood AND solidifies in their intestines. It’s an ugly way to die but hey, they made their choice when they broke detente and invaded.
AND it’s been known to cause psychotic reactions in humans when ingested! What more do you want?
Seriously, out here in the Blue Ridge we get invaded every fall when the weather turns cold. Even with 5 cats and two greyhounds we can’t bring them all down ourselves. Live traps? Then it’s a race to see who gets back inside first. I’ve considered tagging the damn things as a research project…
So go with Warfarin. It’s cheap, it works, and with a name like that you know it has to be good.