A friend of mine used to work at his dad’s glass shop and gave me a can of Sprayway glass cleaner, this was about 5 years ago. The stuff works great. Doesn’t leave streaks like windex and every other glass cleaner I’ve used.
The can looked like this:
After that can ran out I forgot about it since I couldn’t find it locally at any of the glass shops. Just the other day I found out that Costco sells it! The can looks different (slightly smaller can, and has pictures of a sky w/ clouds). I’m guessing its the consumer can opposed to the more industrial can. But the product is the same. It comes in packs of 4 cans, for a little over $6. IMO thats a steal!
You can also find it online at various stores, just search google for “Sprayway Glass Cleaner” and you’ll find find a good deal of places that sell it.