One of the most effective measures to remove rats from the attic is using electronic rat repellers, which drive rodents away from your home by ultrasound waves. If this fails, you can use the electronic rat traps ( Rat Zapper traps are the best of them now) - but it is important to remember to keep attic clear and remove dead mice corpses. An alternative is using traps poison baits, which kill rats by dehydration - we have told more about this method in the review of the best chemical rat poison baits.