There are several myths floating around about cleaning windows, largely borne out of the fact mat because windows are transparent, any cleaning job that leaves even tiny amounts of residues will be noticed. This is not the case with hard surfaces or clothes, for example, where small amounts of residues remaining behind will not be noticed.
The greatest challenge with glass comes from its very molecular composition. As it is composed mostly of oxides, there are a lot of oxygen atoms in the structure. Oxygen atoms are very electron rich which gives them a natural negative charge. The problem with this is that dust is positively charged and windows can therefore become magnets for it.
An interesting exercise to try is to rub your finger down a glass pane, and then rub another finger along a desktop nearby, and compare the dust on each finger. You will probably find that the glass had more dust than the desktop, which may surprise you as it is a vertical surface.
So how do we clean it?
The simple answer is to use QACs, as they are positively charged. They therefore stick to the glass and present a positive charge to the incoming dust, repelling it. The market leader for years has been Windex, as it combines a QAC based formula with a streak-free finish, and simply has no serious competitors. It will clean your windows and help prevent them becoming dusty again for a while.
A home based formula for cleaning windows would simply be an ammonia solution, at a 1 in 10 dilution. It may not produce a perfectly streak-free finish, however, due to the addition of a clouding agent in many ammonia solutions that are bought over-the-counter.
One of the more popular home remedies that is going about is the use of vinegar. Whilst vinegar is a useful home cleaning chemical in various applications it is the wrong choice of chemical for cleaning windows, as it is negatively charged, and while it will do a very good job of removing any dust that is on the windows, it will leave behind a negatively charged coating that will attract dust.
Regardless of what you are using to clean windows, however, you will maximise your chances of getting a streak-free finish if paper towels are used.