Some of the methods used to achieve sterilization are:
High efficiency and cheap. Not suitable for heat sensitive objects.
Hot air oven: inefficient compared to automatic clappers.
Ethylene oxide: used for hot sensitive items, but left toxic residue on sterilized items.
Cryogenic steam and formaldehyde: instruments suitable for chamber or tubular openings.
Fungicide: usually used as a disinfectant, but can also be disinfected when used for long periods of time.
Irradiation: gamma rays and accelerated electrons are excellent in sterilization.
Gas plasma.
