Ice!
I was once bought a "car windscreen ice protector" by someone a while after it had been brought up in conversation and I'd said I absolutely, under no circumstances, would want one, ever. Perhaps I'd been unclear on the, "I'm a healthy person with functioning limbs and some limited hand-eye co-ordination, I can use an ice scraper" section of my tirade.

The idea behind it was a plastic sheet that you wrapped around your windscreen and trapped in the door seals, with a couple of suckers near the middle to help hold it down. However, I can only assume it had been designed by someone who had never seen a motor vehicle in their life. Or any weather, for that matter.

For a start, it was smaller than the windscreen of my (relatively small) then-car. Which meant the whole "trap in door" operation method wasn't really an option. With encouragement to use it I eventually compromised on putting it on one half of the windscreen, with the suckers and driver side door holding part of it down and the rest flapping free in the wind. At least 33% of my windscreen would be ice free, surely? The mystery purchaser would be able to be 33% smug, right?

Wrong. The manufacturer's clever sucker idea meant that the windscreen ice protector stood proud of the windscreen. Which meant condensation and ice happily collected under it. So upon peeling the thing off in the morning I was confronted by two thirds normal windscreen ice, one third impenetrable layer of super-ice.

It took a long time to defrost the car that morning. The windscreen ice protector did not get used again. It must have been that the design notes got lost in translation and "protect windscreen from ice" became "protect ice on windscreen".
(Timberwolf, Thu 29 Sep 2011, 19:23, 3 replies)

Fill up a hot water bottle and place it on the top of the dashboard just before you go to bed
on a frosty night. No frozen windows in the morning.
(WillI'mNot logs in twice a year, every year, Thu 29 Sep 2011, 22:01, closed)

This should be a Top Tip
One without irony. I think I might nick your idea, as my Celica's heated rear window is approximately as effective at demisting/de-icing as Frosty the Fucking Snowman.
( shinyshinyscalp less a man, more a way of life, Fri 30 Sep 2011, 16:15, closed)

Newspaper?
Cheap and easy. Just like me.
( jakedamusss I understand, and dont care., Fri 30 Sep 2011, 6:00, closed)