Homemade Windex for $.27! Here's what you need: 1 Empty Windex Spray Bottle; 1/8 Cup (1oz) White Ammonia; 1/4 Cup (4oz) Isopropyl Rubbing Alcohol; 1 Drop Laundry Detergent. Water - To Fill The Bottle. Isn't it nuts how most of what we're paying for is WATER? Anyway, I tried this "refill" of my Windex and it's awesome! No streaks it even smells like the real thing!