A method for the removal of debris (75) from an aperture (60), the aperture comprising a first aperture diameter (64) and extending along a first axis (62) over a first distance (63), the method comprising the steps of aligning a beam of energy (80) with the first axis such that the beam of energy is coaxially aligned with the aperture, the beam of energy comprising both an energy sufficient to remove the debris, and a first beam diameter (82) which is less than the first aperture diameter; and, exposing the debris to the beam of energy in order to remove the debris from the aperture.