Hi Debbie, Here's a link that may help: https://missmustardseed.com/cleaning-sealing-chipping-antique-pieces/
Happy Holidays!! :)
Hi Debbie. I'm Cindy. You should be OK to clean the window with glass cleaner like Windex. Cleaning it should not affect the patina. If you're worried about the patina, you could always apply a spray sealant. Good luck Debbie and Happy Holidays.
Thank you Cindy I’ll give it a shot sounds like a great idea and not too much work. Happy holidays to you Debbie