

The best way to clean glasses is with your fingers using warm water and dish soap. Don’t use super hot water, it can damage the coatings on some lenses. Start with a rinse to remove any particles, then clean them between your fingers, then a final rinse, shake them off and let them air dry.
Using any type of cloth can cause scratches as you’ve found.
I think we all know this, but it’s the exact same argument for Facebook and Twitter and LinkedIn. Getting off centralized, corporate, for-profit cloud services should be a priority for anyone who is philosophically aligned with FOSS.