A method for disinfecting or sterilizing an article comprising enclosing the article or article part inside a container having a wall of which at least a part is a semipermeable fabric or membrane and introducing an amount of vaporizable biocide, preferably hydrogen peroxide in water, to the interior of said container in solution, vapour, liquid or preferably nebulant form. The semipermeable fabric or membrane is selected to allow the biocide to pass from inside to outside of the container as a vapour at atmospheric pressure and to provide a barrier against entry of micro-organisms. The biocide is allowed to exit the container through said membrane while at or above atmospheric pressure, a fluid eg air is directed to flow adjacent the outside of the membrane to expedite vapour removal from the interior side. The article is exposed to the biocide for a time sufficient to disinfect or sterilize the article.
