Removing Old Insulation Can give you a fresh start from an attic that has been infested with Rat Droppings, Raccoon Poop; Insulation that is wet from a leak or mold.  Replacing your old Insulation can also reduce harmful dust that is finding its way into your home,  irritating those with bronchial or allergic issues. It is not always necessary but can be the way to a new beginning in the air quality of your home.