Here’s a simple concept to embed a squeegee into the edge of the window so that when you open it, the other window gets cleaned. But what happens to all the dirt- does it just get piled onto one side? And what about the other window? Obviously it still needs some work but in theory it’s a good start to something.
8 in 1 Mini Gadgets Electric Repair Tools Pen Style Precision Screwdriver Set Kit, Home Improvement (Green)