I agree. As any wearer of glasses knows, a clean cotton t-shirt beats anything for cleaning an iPhone as well. Microfiber "cleaning" cloths are horrible as they simply spread oils and smudges around on the screen indefinitely.
Obviously, never use your shirt if you have bee to the beach or work in a field where you could have contaminated your shirt with fine yet hard grit from metal workings, sand, etc... Otherwise, skip the specialty cloth and go right to your t-shirt whenever needed.
