Whilst not really being one for cleaning cars (generlyy that's what we have rain for!)

However, on the odd occasions I do it, & after rinsing (& once or twice) leathering the car off, I notice the screen

Is there a product/technique that will make the swept area disappear??, or to be more precise, make the unswept area not be so 'outstanding'??

On the other side of the coin, I do scrub the alloys (generally with one of those little foam washing up pads), as I have no desire to see the brake-dust take the lacquer off

The only real way to remove the 'swept area' as you mention it would be to use a specific glass cutting polish to re-fine the surface and remove this swept area........:(

If you have access to an old-fashioned pharamacist (not just chains like Boots or Lloyds), ask them for "precipitated chalk". Dust the screen with this, then wash it off with lots of clean water. Be prepared for very squeaky wipers for the next few weeks though.

Thanks guys, I had thought that it was maybe the most 'microscopic' layer being removed by the abrasive action of the wiper blades.

It's not really an issue, because as I say, washing is something that nature does for me - but, I do vacuum the seats/carpets, clean the internal glass, wipe the dash, etc... weekly

After all, I don't sit on the outside of it