Decon dehydrates mice. They'll load up on the little pellets and take them back "home" for snacks. They keep munching the pellets off and on then die someplace else from dehydration and usually desiccate before they rot, no smell. There's a warning on the box to prevent children and pets from ingesting the pellets.
Here's a product that live traps 'em really well, if you want to relocate the little pests to somewhere that may deserve them. About $1.00 at Wal-Mart, Mice-Cube:
