My problem is frost on the inside. It was 10 below this morning and after coming out of the humid garage and sitting in the church parking lot, all the windows were frosted solid on the inside. Couldn’t see a thing. Scrapped a little peek hole to get the car pointed to the sun and wait for the defrosters to work. About all you can do.m The tri-fecta-Humid garage, short trips, and colder than heck.
–Much exterior/ interior fogging/icing happens because the condensation on your warm glass freezes. So lower the condensation! A few blocks before you park the car turn off the heat, and crack the windows about an inch until just before you leave the car, when you can close them again. It sounds masochistic, but you are going to be cold anyway as soon as you leave the car. Maybe this is just wishful thinking, but not closing the dashboard vents seems to help a little (our small truck interior would form condensation unless I left the vents open).
–covering the windshield can help. Most car parts stores have $5 - 10 covered sheets, which work better than flimsy plastic bags. If you park with the front facing uphill you will get less ice or snow beneath the shield.
–I’ve tried all kinds of vinegar this, alcohol that, and they all either seem to streak heavily, work poorly, or look like they will damage your paint or your dashboard. Diluted Rain-X worked fairly well but apply it on a warm day and expect streaks. Some of the commercial sprays work OK too but they have some risk of paint/seal damage.
–remote starters and waiting until the defroster clears the windshield can work but they waste gas, pollute the air we breathe, and put more wear on the engine (te best way to warm up a car is to get it up to operating temperature reasonably quickly).
–simply cleaning your windshield and window, if you can, may help prevent condensation around dust particles, which act as nuclei for ice formation.
–winter wiper blades can clean the windshield better with less ice buildup on the wiper, but they put more stress on the motors.
–No trick will keep all the ice off, so get a good scraper, perhaps with a mitten attached to it. Also clean the nozzle area for the windshield washer fluid, with a pin if necessary.
Instead of trying old wives tricks, try an ice scraper.
Seconded. And if you forgot to get an ice scraper, a credit card works just as well as long as it’s just frost and not solid ice, and is one of the only things you can use it for that won’t cost you any money. 
@shadowfax is right.
In lots of winter weather it’s better to drive with the defroster off, if possible. Opening a window or two just a bit, with the heater on but blowing on the floor only, usually kept the windshield clear and cold, so when you stop the moisture doesn’t seem to accumulate on the glass. It also works better when it’s snowing, because the snow doesn’t melt and smear dirt all over the glass while you are driving. It blows off the cold glass.
None of that helps if it snows or you get freezing rain overnight. Then, use a plastic scraper or cover the windshield when you park.
For my 12 years in Anchorage a scraper + full on defroster at max heat worked. Not using the defroster while driving guaranteed a fogged window. This is where rubber floor mats help - dump out/clean out any tracked in snow. Carpet mats soak it up, constant source of humidity.
I remember snow; ice; and frosted windshields, but I am trying to forget.
Park at night in shelter ,stop driving when weather is bad if possible (works for me ,I dont intend to be in the slick weather gymkhana again if possible ) .
The times I’ve had problems with frost or fog on the inside of the windshield were when I got into the vehicle covered with snow… my clothing covered with moisture. My '89 pickup didn’t have AC, and until the engine warmed up there wasn’t much I could do but wait. I had too much moisture coming off my cloths and depositing on the cold glass.
When it’s a blizzard outside and you have no AC, there only patience works.
I used electric heating to melt the ice on the windshield of my Chevy Citation. My homemade heater was positioned under the windshield. The car didn’t need to be running to operate it. It drew about 500 watts of power and could start melting everything off the windshield in about 30 seconds. After about 2 minutes the ice and snow was pretty loosened up and most all just sliding downward. An added benefit is that it began to warm up the inside of the car right away.
Here is the link I found from WATE in Knoxville, TN: http://wate.com/2016/01/05/how-to-quickly-and-safely-remove-frost-from-your-windshield/ Still not sure about this and potential damage to paint, coatings and rubber parts like seals and wipers.
@JBofEastTN This is the second time you have posted this link, I wonder why. Your first post was 1/7 it seems by now you would have decided what works best for by now.
If you have doubts about using something then don’t.
I Just Bought A New Window Scraper, A 60" Polar Vortex!
It’s got two ice scrapers, a wide folding snow broom, squeegee, and 3 foam grips!
It hasn’t stopped snowing here for over week and that snow broom is great for vehicle roofs (even on the van) and windows.
It retracts to something shorter than the 60 inches and the broom folds parallel to the shaft.
This thing has become a necessity for me after the first time I used it. It was 20 bucks, including tax.
CSA
Hey CSA, do you realize how rare it is for someone to actually clear the vehicle roof of snow? Give yourself a gold star.
@VOLVO V70: I added the link just yesterday. Look at the edit time stamp on the two posts. Also, although it has been cold, the car windshield has yet to frost over. There has been no way for me to decide what works best.
I have a technique that I rarely see elsewhere. I keep a collapsible shovel in the car. Since it is made of plastic, I use it to remove snow from the car, much faster than a scraper. Once that removes 90% of the snow, I can use a long brush/scraper for the rest.
But you have to do this when the snow is fresh, before it can change to ice.
Best method when possible,park in a carport (best investment I ever made with saved allowances )
“There has been no way for me to decide what works best.”
What “works best” is an ice scraper. Why are you dead-set against it?
I always clear the roof of my Accord of snow. If I was driving the Silhouette, I probably wouldn’t though.
Rubbing alcohol that you buy in the store is already 1/3 water. When I used to drive from Buffalo to Watertown and Montreal, night time temps were frequently -25F to -35F. One night I even saw a -43F on a bank thermometer. We used pure isopropyl alchol for wiper fluid ( The company bought it in 55 gallon drums) It worked pretty good, but if it was cold enough and windy enough, the windshield would still refreeze,
Did it hurt the paint? Don’t know and didn’t care, the object was staying alive. We had no CB radios or cell phones back then. You didn’t pass a broke down driver, no matter who he drove for.