Make Your Own Windshield Washer Fluid!! Here is an easy do-it-yourself recipe using basic household ingredientsYou will need: 1 empty (clean) gallon jug 1 gallon water 1 tablespoon dish soap (use whatever you have on hand. I used Dawn) 1/2 cup non-sudsing ammonia (Note: You can substitute vinegar for ammonia if you prefer) A few drops of blue food coloring (this is optional, but it's a reminder/warning)Fill an empty gallon container with water. (This is a good way to repurpose 1 gallon plastic vinegar jugs, which I seem to go through a lot of!) Add, dish soap, ammonia, and food coloring (optional). Recap the bottle and gently tip upside down a few times to mix ingredients. Pour into your car! This mixture should work in most climates…but when the weather dips below freezing, add 1 cup isopropyl alcohol. If you’re concerned about whether your homemade mixture will freeze, leave it outside overnight (in cold weather) and check it in the morning. If it’s frozen add additional alcohol! Little did I know how simple it was to make…and little did I know that commercial windshield washer fluid contains a nasty chemical called methanol, which the National Institute of Health lists as a poisonous alcohol that can cause significant damage even in small amounts. Yikes.