This is something we deal with on a regular basis. If you have this significant of guano buildup, we suggest letting us inspect your property for any other potential entry points. When the bats are evicted from the vent, they will naturally look for another way into their — or in this case, your — home. Also. while you may not see bats in the attic or home, you are not necessarily in the clear. The urine and guano of bats are very corrosive and can deteriorate the bottom of gable vents. Eventually the vent will rot and bats will inhabit the space between the walls and brick, siding, or rock. Don’t procrastinate, as guano can build up fast inside these voids. This not only causes the health risks you hear about but can attract other bats for years to come.