Note: Close test tubes, flasks with media etc. with nonabsorbent cotton and if possible wrap in clean, dry paper. All glass wares to be sterilized should be clean and dry. Liquid content of the bottles should be not more than ¾ full and should be closed loosely with screw caps. Media flask to be sterilized should be plugged with cotton and the plug should covered with the wrapping paper tied with a string around the neck of the flask. Disposable plastic material is sterilized by the manufacturer and should be used once and should not be sterilized in the autoclave.