Use an automotive glass cleaner and two microfiber towels, one to clean, one to buff dry. Clean the inside last, and roll windows down to get the top edge.
Why windows streak
- Too much product
- One towel doing both jobs
- Cleaning in direct sun so the cleaner dries too fast
- Interior film from off-gassing and smoke
The two-towel method
- Wipe with a dampened cleaning towel
- Immediately buff with a dry towel
- Wipe outside glass vertically and inside horizontally so you can tell which side a streak is on
Interior film
The hazy film on the inside of the windshield comes from plastics off-gassing and needs a proper glass cleaner, not just water.