All of the following can be used for sterilization of hand piece except:

Autoclave sterilization of hand pieces is one of the most rapid methods of sterilization. However, fibre optics dim with repeated heat sterilization in several months to a year, apparently owing to oil residue and debris baked on the ends of the optical fibres. Chemical vapour sterilization is recommended for some types of hand pieces- apparently works well with ceramic -bearing hand pieces. ETOX (ethylene oxide) gas is the greatest method of sterilization used for hand pieces. Dry heat sterilization of hand pieces is generally not recommended.