Peanut butter in the 'humane' traps, even if you don't plan to release them humanely, at least you can kill them humanely though it's still
Only that the snap traps sometimes incompletely catch them - they can break or chop off a limb, break their necks/backs but leave them alive, or in one graphic article I read, make them explode
In my case the mouse was so little he actually managed to get his whole body into the snap one, so he was contained in a space almost as big as his body all night, and then still had to be drowned in the morning
Euw. The memories of our mouse days are quite traumatic.