In most cases of high mileage engines, original pistons need replacement due to the requirement of boring the cylinders to a larger size for normal wear compensation; however, if the cylinder walls only need slight finish honing, old pistons may be reused if they are in good condition. Begin by washing the connecting rods and pistons in a cleaning solvent and drying them with compressed air if available, avoiding wire brushes or abrasive tools on any piston part. Clean the ring grooves with a groove cleaner tool, ensuring the oil ring holes and slots are also clean. Check the rods for twist, bending, nicks, or cracks, replacing any damaged rods. Inspect the piston for cracked ring lands, skirts, or pin bosses, as well as worn or wavy ring lands, scuffed skirts, and eroded areas at the top; any damaged pistons or those showing excessive wear should be replaced. Look for nicks in the ring grooves that may cause the rings to hang up. While the piston is still connected to the connecting rod, swivel the rod back and forth to assess the degree of difficulty, comparing all piston/rod assemblies; if the rods are loose on the piston pins with little or no drag, the piston pins are worn and need replacement. If the cylinder block requires any machine work, including finish honing, the machinist will likely want the pistons on hand to check piston-to-bore clearance, a critical measurement best handled by the machine shop.