Lens manufacturers say that anything other than a microfiber cloth will damage the coatings on a lens. But microfiber cloths eventually pick up crap and they look like they're a pain to wash.
How do you keep your lenses clean? Are you using cloth/kleenex or microfiber cloths? If you use microfiber cloths, how do you clean those?
I bought so many microfiber cloths that when one gets too dirty, it goes to workshop duty and I get a new one for glasses.
For cleaning lenses properly (which I do once a week or so), I tend to use lint-free tissue (Kimwipes) and a mixture of 85% petroleum ether & 15% pure isopropanol; both of which should be available at your local hardware store. Bonus is that this is also appropriate for scientific optics, like microscope/camera lenses & instrumentation components (mirrors, prisms etcs) - just don't rub them!