Bumpers tend to get the brunt of minor bumps and fender benders to vehicles. As a result, the bumper can get dented, broken, cracked, or scratched. Out of all these types of damage, the easiest to remove is a light scratch. I would also add that sometimes these “scratches” might actually be paint transfer, where paint has rubbed off of another vehicle onto yours. Paint transfer and light scratches are both easily removable with a machine polisher and compound/polish. If the paint from your bumper comes off, then you will need to resort to either a bumper respray or touch-up paint.