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?
My mother did that so I ended up doing the same in elementary school. It took me a while, but I realized how disgusting it was and have been using cloths, or my shirt, for most of my life.