Washing windows is probably at the top of the list of household chores we'd rather avoid. We spend hours scrubbing the glass with old newspapers or rags, fighting annoying stains from every angle of light, and then - as if by magic - the very next day it rains or the wind blows dust. All our hard work is ruined in an instant, and the windows are once again covered in dirt, despite the fact that we've spent too much precious time and a lot of money on aggressive chemical cleaners to achieve a sparkling result.