Breath and my shirt. But I also have a Zag on it.
I have Verizon's relatively cheap screen protector on mine and the shirt method works for me as well.
Why waste the money on a screen protector? Naked is the way to go! For the most part my holster lining is enough to keep mine clean, if not any handy cloth works.
I also use a microfiber cloth. It helps that I cut up one and sewed it as a lining for the cellphone compartment of my purse.![]()