How to clean the buildings exterior surfaces of glass panel of 25 m height?

By different methods

1) Aerial work platform by skilled manpwer using ScissorLift

2) Suspended Platform or cradle, rails

3) Windowsill access

4) Automated Facade Cleaning System - GEKKO

Uses Suspended platform to perform this particular activity.

like.

1. Using of cradle to clean the glass

2. Rope way access

3. suspended boatswain`s chairs

NB: need competency for using such equipment.