Water fed poles:

We deliver pure water to your glass and surrounding window frames via a water fed pole, which is a very strong and light aluminium or carbon fibre pole carrying pure water to the soft bristled brush head especially designed for cleaning glass.  The window and the frames and sills are gently scrubbed if necessary with the brush to loosen the dirt, then the dirt is rinsed away with gentle jets of pure water.  

The glass is left wet once cleaned, to allow them to dry with the best possible result.  The last thing to touch the glass should be the water.