My sister tells me that spraying rubbing alcohol on a windshield thaws out the ice in a few minutes? Is this true?

Given that it's melting point is -89 C and it's miscible with water, it sure will work.

But given that it's about 15 bucks a gallon (70%) and 34 bucks a gallon (98%) as opposed to windshield wash antifreeze which is good to -40 C which goes for about 5 bucks a gallon, I'll stick with the windshield washer except in extreme emergencies.

Alcohol and water together freeze much colder than water without alcohol. Pouring alcohol onto ice will dissolve the ice and the result will be liquid.

True, yes.

Sure--look up the ingredients in windshield washer fluid, and you'll find that methanol (wood alcohol) is the primary component. Alcohols have far lower freezing points than water.

.

.

I'm not sure. But in any case you should not be spraying a liquid that was made to be rubbed.

It's also likely to lift the paint on the car - that's my experience.

Be careful, if the temperature is below 20F it will instantly refreeze

Try it. I think you'll find out that it works.

yes.