Getting a smear free, clean, window or picture glass is not easy. Dust, pollutants (oily and sooty), fly blows, fingermarks all tend to smear when rubbed. Normal detergents (oily or solid) needed to disrupt and hold these pollutants in water suspension/solution remain as smears. Even a tiny amount of surface contamination is glaringly obvious.
Isopropanol, acetic acid etc mixtures in water are fairly good at the disruption bit of the process, but not so good at suspension.
Is there a volatile surfactant (even if inefficient) that can hold the contaminants in the liquid long enough to get them off the glass surface into the paper or cloth wiper? The excess surfactant could then be left to evaporate at leisure.
Or is it the old method of multiple dilutions with clean solvent on a succession of lint free wipers the current state of art?
It is an old unsolved practical problem.
Any ideas welcome.