A method of cleaning a contaminated surface, such as cleaning the elongate interior lumen of an endoscope contaminated with flesh, bone, blood, mucous, faeces or biofilm, said method comprising the steps of: providing a suspension of solid particles in a liquid to said contaminated surface, and flowing said suspension along said surface thereby to remove contaminant from the surface. The suspension is preferably an ice slurry, where the solid material is ice crystals. The slurry preferably has a solid fraction between 50-85% by volume. A freezing point depressant may be present.
