Next, I inspected the basement, which was mostly an unfinished basement, so it was not regularly visited or inspected for rodent activity. During my basement inspection, I observed prodigious quantities of mouse droppings on the sill plate boards and shelves. (See photo where mice had burrowed holes in the basement insulation.) This was an older home, and it was apparent that mice had free reign to come and go as they pleased to escape the harsh outdoor elements for many years. First, I placed numerous snap traps on the sill plate where, based on the droppings, there was extensive mouse activity. To definitively resolve this problem, I needed to seal the access points to the basement from the outside. To resolve a mouse infestation, it is critical to locate and seal all of the potential mouse entry points around the home's perimeter.