<prompt> Autoclaving is not useful for disposal of:Surgical dressingsMetallic instrumentsPetri dishesLiquid paraffin  <response>: Ans. d Liquid paraffinRef : K. Park 23rd ed. 128 Autoclaving is a method of disinfection mainly used for surgical dressings, instruments, laboratory wares, media and pharmaceutical products. Principle: Steam High pressure 30 psi and temperature 121 C. Efficiency test of autoclaving: spores of Bacillus Stearothermophillus. 