Narrow Gaps - What would you do?

I just quoted a job that has a fake balcony where the railing comes out a couple inches from the door. It’s narrow enough I can’t fit my arm in past my wrist, so a couple inches clearance.

I’m sure I can design and make a low profile squeegee to be able to clean it, but is there already something out there that will handle this?

I also have a WFP and just had the thought of using a spray bottle and a scrub brush. Wet the window with Dawn water, use my T-bar on a pole to scrub and then rinse with RODI water from my WFP?