Biofilm and debris can be removed from the interior and exterior surfaces of small bore tubing by passing an aqueous cleaning solution of water, one or more surfactants and preferably a source of hydrogen peroxide, optionally including small inert solid particles, together with a gas under pressure, to create a turbulent flow within the tubing that loosens the biofilm and debris so that they can be flushed from the tubing. When the exterior surfaces of tubing are to be cleaned, the tubing is inserted in a sleeve fitted with an adaptor that provides a pressure-tight seal between the tubing and the sleeve.