Egg Shells: Check behind your books or plates on shelves for small dark brown cases.
Shed Skin: Check along the walls for molted skin, often you will find complete body casings.
Droppings: Cockroach faecal matter often looks like small black sand. The larger the roach, the larger the droppings
Cockroaches are not only a nuisance, but they bring with them many health concerns: