Abstract: A method and apparatus for cleaning layers of earth that contain noxious material via a cleaning medium that takes up the noxious material and is introduced into the layers of earth via a drilling tube. The cleaning medium is extracted by suction from the layers of earth and is subsequently processed. To achieve a precise cleaning on the spot in a continuous manner without the necessity for excavating the earth, the cleaning is effected within a chamber that surrounds the drilling tube. The chamber can be lowered into the ground either together with or separately from the drilling tube. After termination of the cleaning process, at least parts of chambers used therefor are removed from the ground and shifted to a region that has not yet been cleaned, resulting in an advancement of the cleaning process in a horizontal direction. A sludge mixture can also be pumped from the chamber into a cleaning unit, with the clean, recovered earth again being introduced into the chamber.