The most commonly used method for sterilizing surgical instruments is autoclaving because it uses steam under pressure to achieve temperatures above 121°C, effectively killing all microorganisms including spores. This process ensures complete sterilization in a relatively short time, preserving instrument integrity. Unlike boiling or chemical methods, autoclaving provides consistent and reliable sterilization necessary for safe surgical practice. It is the gold standard in healthcare settings for preventing postoperative infections.

Reference: Medical Microbiology, Murray et al., 9th Edition.