Squirrels Leave Droppings and Urine in the Attic
When squirrels live in your attic, they also use it as their personal toilet. Squirrels have a high metabolism, eat a lot,
and leave behind up to 20 droppings a day. They also urinate quite a bit. The droppings and urine not
only smell bad, but they pose a biohazardous risk, and the smell attracts new squirrels. Squirrels, like all rodents, depend
upon smells that both mark territory and serve as a sort of scent map to help familiarize them with their environment. Once a
squirrel has scent marked an area, squirrels years into the future will know that the area is a good squirrel habitat, since
squirrels have successfully thrived there before. I highly recommend
attic decontamination & deodorization services if you've had squirrels living in your attic.

Here is a very heavily soiled attic.

Squirrels not only leave a lot of droppings, but they bring in nuts.

Here is a big pile of droppings all in one spot.

Here is a nest made out of leaves, with a bunch of droppings.