I'm constantly switching between prescription sunglasses and regular glasses and have always fiddled with wrapping them in small thin microfiber cloths before putting them in the case. I replaced those stupid rags with these things. It protects the glasses in my pocket and is a good cleaner if I ever need to wipe them down. This is a really brilliant, simple idea that I wish someone had thought of before. I love MagicFiber as a brand in general, have bought many wipes from them over the years including a large one that I use in my laptops to protect the screen from keys and key oil (yes it's important, I used to have many controlled by laptops). for work and you can see who protects their screen from keys and who doesn't).