The finishing begins with the separation of the individual parts from the tree and metal reservoirs they are attached to. Abrasive saws and table saws are most commonly used because of the ability to closely cut along the part surface. These contact areas must also be ground flush to the part. Other grinding can be required after inspection and at times cosmetic welding can be performed. With most metals heat-treating is necessary to optimize strength and ductility, corrosion resistance or other properties of the metal. Surface preparation completes the finishing process with shot or sand blasting to yield a uniform appearing surface. A distinction of the investment casting process is the use of finer grit grinding and blasting media than what is usually found in other processes.