Deny them food and water. Did you wash your dishes and put food away promptly after meals? Did you clean up spills right away and keep the area clean especially in the kitchen?
Take out the trash regulary. Did you have one trash can for food in you house? Don'y let it sit for too long. Use a trash can with a lid, rather than one that stays open. Is there any cracks on your cabinets, windows and floors? Fix all the cracks otherwise it will serve as there hiding place.