The invention relates to a method for cleaning filter structures of filtration installations for filtering liquid products containing a gas or gas mixture that is neutral to the product, in particular for filtering drinks containing the gas or gas mixture that is neutral to the product. A list of user roles comprising each user role in the data repository that is associated with the website is determined. A Fourier optical system directs a portion of the scattered light onto an array consisting of multiple photodetectors. Each clamp portion also has a recess of part-circular section and the bar is received and clamped between these recesses. The first slurry has a copper to barrier polishing selectivity of greater than 30.