I was once steam cleaning some chairs at my school, but the steam cleaner wasn't good enough so we decided to use a wet/dry shop vac instead. As soon as we turned on the vacuum this awful smell of feces, burnt hair and rotting vegetables began to emanate from the vacuum. We opened it up to see what was inside and saw that the janitor had used the vacuum to clean up what looked like a hideous melange of hair, vomit, and garbage, and had left it inside the vacuum in a hot closet over summer vacation. It was terrible.