A system and method of cleaning an enclosure of a container defined by inner walls, including providing a container, orienting the container so that the opening is lowermost and opens downwardly and generating resonant vibration in the container at a predetermined frequency and at an energy level sufficient to dislodge any loose solid particles from the inner walls of said container but not being of an energy level to impact the structural integrity of the container and maintaining the resonant vibration within the container enclosure for a sufficient time to dislodge all loose solid particles from the inner walls of said container. The system may include a resonant chamber in the form of a shroud and means to effectuate the method steps and may also include a sanitizing step in which the containers are further sanitized to render inactive any organic contaminants.