Casing Scraper for Well Drilling The Casing Scraper is used to clean cement, mud, embedded bullets, rust, mill scale, paraffin, perforation burrs and other substances from the inside walls of casing. Maintaining a clean casing I. D. is important to the operation of all tools used in drilling the well. Likewise, packers and similar tools must have a clean surface to grip. Foreign materials on casing walls will frequently cause these tools to become difficult to operation. The Casing Scraper is ma