Removing the damaged area and replacing it with a new section would be ideal for small damaged areas of the roof. Dirt and gravel from the damaged section of the roof should be cleaned by grabbing a broom and sweeping it clean. The gravel should not be discarded and can be used for repairs. The damaged area can be removed by using a straight edged utility knife. You will need to put some effort for cutting a rectangular section of the roofing material.