An instrument (28) or other item to be sterilized is supported on a hanger (26) in a decontamination chamber (10). A container such as a sleeve (92), is supported at adjacent ends between supporting rings (90) such that the container surrounds and is displaced from the instrument. A pump (40) recirculates a sterilant or other antimicrobial solution that collects in a lower drain (48) and a reservoir (50) through spray nozzles (70, 96) and connectors (44) which are connected to interior passages of the instrument. In this manner, the internal passages of the instrument are sterilized by the flowing liquid and exterior surfaces are sterilized by sterilant solution mist which condenses on and coats the exterior surface. After the instrument is sterilized, a sterile rinse is sprayed on the instrument and interior of the container. The container and instrument are removed as a unit and the container is closed at its ends to prevent the instrument from becoming microbially contaminated from the ambient air. The instrument may be dried passively by a microbe blocking filter (98) in the container or by using a fan (80) to pump drying air longitudinally through the container.