thats rubbish rosskesava.not true at all.ive cleaned some ground floor windows trad this week in low sun and they were perfect.granted it was squeegee off i was using but ive checked with ecover before and no problems whatsoever.
good soft rubber in my squeegee
not too much detergent in my bucket
flatweave microfibres for detailing.
i check the window at an angle when tradding any ground floor windows once ive finished in low sun.
i agree you can leave streaks IF you use too much detergent in your bucket and a less than new rubber in your channel.
if you use fairy and put too much in your bucket then your asking for trouble IMO.
I stick with ecover,squeegee off or gg3.whatever i have in my van.
regards
dazmond