If it’s just grime and hard water, this is the best I know of that 100% won’t do any damage yet still give a perfect finish. Sprinkle it on a wet windshield and buff away.
BON AMI 1886 Formula - 12 oz (Pack of 2)
https://a.co/d/i7wuure
The original formula has no abrasives. Ace Hardware usually has it for under $2/can or can order it. If you’re actually buffing out scratches you need something stronger.