I looked for a long time for an answer to streaking when I cleaned my car windows. I finally found the answer on YouTube. The answer I found was to make your own solution because commercial products like Windex just didn't work worth a darned. At least they don't work for me in giving me the results I want. In addition, I found it works great as an eyeglass solution. I went to Walmart and bought a spray bottle and mixed the solution in that. I use that with a microfiber cloth on my car windows. I put some in a spare pocket size eyeglass cleaner bottle to carry in my purse for my eyeglasses. This is what works for me. No more streaky car windows or eyeglasses.
50% distilled water (4 oz)
50% rubbing alcohol (4 oz)
1 tablespoon white vinegar