window-cleaning services./ prequalification of window polishing at the national association of municipalities (kl) oct 2022./ kl offers window polishing for their residence of approx. 12,500 m2 cleaning area. the building is predominantly used for administration and meeting business. be aware that it is a complicated task, both in terms of accessibility and use of lifts. it is a requirement that part of the facade glass must be polished by rappelling, as the polishing takes place over a basin.