The limestone surfaces around the entrance portal which are subject to graffiti, have been coated with PSS 20 to provide protection against graffiti attacks. The graffiti is removed by PSS Interservice. The floors in the stairways, including the landings, are protected against dirt with the help of Faceal Oleo HD. Faceal Oleo HD makes cleaning easier and creates a significant self-cleaning effect when it is raining. The graffiti is continually removed by the Service Department of PSS Interservice AG.