| Use the air-con to provide dry air it will demist a lot quicker. For a longer term solution you can also buy anti-misting pads or sprays. Go to autoexpress web site and click on products they recently compared the anti-misting formulas. Better not to get misting rather than clear it quickly.
Some people are like a Slinky ........ not really good for anything, but you still can't help
but smile when you shove them down the stairs | 
