Sebum stains are used to identify mice activity. Sebum is oil from the sebaceous glands. Think about what is know as “ring around the collar.” That is a discoloration to a shirt collar from sebum. Sebum from rodent fur is left on runways. The more the runway is used, the more sebum builds up. This is
known as a rub mark. Use rub marks to effectively place your rodent traps or bait stations. Finally, use rub marks to identify entry points from the outside.