cctvdomecleaner

Hi I know the subject of CCTV dome cleaning has been touched on in this forum but no solution to the problem of cleaning a CCTV dome that is already dirty. We have a CCTV camera mounted over 20 feet high on our building that is filthy but have no means accessing it with a ladder to clean it. Does anyone know of a product for cleaning a CCTV dome without damaging it from a distance like this? Many thanks in advance!