The purpose of the Scraper Blade, or Scraper Bar, is to loosen the harder ice slush and stuck-on snow in places where the softer snow paddles are unsuccessful. Scraper Blades are designed to wear as they scrape and therefore are a very common replacement part for a snow thrower. Once a scraper blade is significantly chewed up, it will no longer make optimal contact with the paved surface. The height can be adjusted up to a point, but eventually the blade needs to be replaced.