Abstract: The present invention provides a waste removal assembly used in conjunction with a sampling system which provides access to a sealed container. The assembly includes a lifting mechanism which moves a sample container against a hollow cleaning needle. The needle penetrates the stopper of the container, and its penetrating end moves into the container proximate the inside surface of the stopper. The assembly also includes a pump and tube arrangement in communication with the needle for removing or displacing entrapped serum or other debris from the bottom surface of the stopper and placing it in a waste container. After removing the debris from the container, the cleaning assembly vents the cleaned container to atmospheric pressure, and the sampling system performs sampling operations through a puncture tube which defines a temporary opening in the stopper of the container.