Courtesy Photo Alpena Wildlife Sanctuary board member Terry Gougeon places a boot brush that he made at the entrance to Island Park. Another boot brush will be placed at the entrance to the bridge to the island. Boot brushes are used to prevent the spread of invasive plants into a natural area. They remove mud, seeds and other debris which might contain invasive plant or animal species. The boot brush station has photographs and names of invasive plants whose seeds can cling to boots and the coats of dogs.