masona, from my late reading of this thread and the one you referred to earlier, I assume you are still trying to sort out ice on the windscreen.
I hope I haven't picked up the wrong stick
Just in case I haven't, I gave up scraping ice off the screen 20 years ago, and I don't use de-icer as it is expensive and it is specially designed (very cleverly) to transmit ice from the outside of the screen to the inside.
Try a 2 litre milk container with water from the hot tap, cheap and effective.
I know, I know it'll crack the screen because of differential expansion. Well nobody thinks about that using de-icer, and I bet the shocks are just as great. Just to prove the point that it didn't crack screens, I had a screen with a bullet crack in it, and I boiled a kettle and took it outside and poured it over the screen. It wouldn't have mattered if it had cracked as I wanted a new one anyway. Well I sold the van 12 years later with the same screen and I had used hot water to clear the ice every time it needed it.
The advantage of using hot water is, it cleans and heats the screen, so when you drive off, the screen doesn't mist up. Try it and see.