Decon ... looks like little bluish/green pellets in little black trays. I sit them in shoe boxes because the little varmits are messy eaters and scatter them. Replace them as they get emptied ... probably daily if you've got a lot of the critters. Once you see they're not eating them any longer, they're gone.
They do not smell when they die ... the Decon dehydrates them and there is no smell although supposedly they leave the premises searching for water.