I know your pain. I'm doing battle with red squirrels* at work.
I spent two days cleaning their "stuff" out of a tool shed,
got it all Popular Mechanics like tidy inside and
now...they're ba-ack!

Trap & drown three, and eight come to the funeral.
Having a few dozen black walnut trees as a food source isn't helping me win the war.

* I generally prefer peaceful coexistence with my fellow critters,
except for red squirrels, as they gnaw their way into wooden buildings,
then gnaw even more wood once inside.