Rat or Mouse Droppings? How to Tell, and How to Clean Them Up

Droppings are usually the first real evidence anyone finds. They tell you what you have, roughly how long it's been around and where it's spending time. They also need to be cleaned up the right way, because rodent urine and droppings can carry germs that you don't want floating around in dust.

Size and shape

Mouse droppings are small, about an eighth to a quarter of an inch, with pointed ends, a bit like dark grains of rice. You'll find them scattered along walls, in drawers and on shelves. Norway rat droppings are much bigger, around three-quarters of an inch, thick, with blunt ends. They tend to show up in piles along a route. Fresh droppings are dark and soft. Old ones turn gray, dry and crumbly.

• Rice-sized and pointed: mice
• Raisin-sized or bigger, blunt: Norway rats
• Dark and shiny: fresh, still active
• Gray and crumbly: old

Cleaning up the CDC way

The CDC's advice is the same for every rodent mess. Air out the space for a while first if it's been closed up. Wear rubber or plastic gloves. Spray the droppings and any urine spots with a disinfectant or a bleach and water mix until they're soaked, and let it sit about five minutes. Wipe it up with paper towels and throw them out in a sealed bag. Then clean the area again and wash your gloved hands, then your bare hands.

Don't sweep and don't vacuum droppings. That puts dust in the air, which is what you're trying to avoid.

When to leave it to a pro

A few droppings in a kitchen drawer are a homeowner job. An attic full of them, a crawl space with soiled insulation, or a shed that's been closed for years is a bigger job and worth handing off. See attic rat removal and cleanup. If you're still finding fresh droppings after you clean, the animals are still active, so start with rat control or mouse control.

See also: Attic Rats and Cleanup, Mouse Control, Rat Control