You can tell if your operation has been infested with cockroaches by looking for signs such as droppings resembling black pepper or coffee grounds, egg cases (oothecae) in dark corners, smear marks along walls or surfaces, and a musty, oily smell. For rodents, signs include droppings, gnaw marks on wires, packaging, or furniture, nests made of shredded materials, tracks or rub marks along walls, and scratching noises, particularly at night.