Went throught the whole 'don't want to kill them' thing a few years ago when we had mice. Used live traps, the little twats just ate the bait of them without setting them off. Called the council in the end who just put poison down, that did it. Didn't see or smell any dying mice. The lad from the council said the whole terrace had them, even if you catch a couple, you'll just get the neighbour's.