Removing materials stacked against the outside of an otherwise rodent-proof building will stop rats and mice from gaining entry into upper stories. Rodent-killing as a single control measure is expensive and effective for only brief periods of time. It is most effective if carried out during the winter when reproduction is at its lowest level. Also, as mentioned earlier, it is best to sanitize and rodent-proof prior to killing rodents when possible. If rodent infestations are severe, it may be better to kill the rodents first, because removal of harborage may cause them to migrate to nearby buildings.
Trapping is a common method of rat killing.
Traps may or may not be baited but should always be placed in areas of rodent activity. Bacon, peanut butter, bread, and nutmeats make suitable baits. To be most effective, they should be placed with the bait toward and the spring away from the wall.