Let me offer up a product which has given me some satisfaction for a couple of years now. It is the 3M microfiber Lens Cleaning Cloth. It measures 6x7 inches.
I clean my plastic polarized fishing glasses, my regular plastic prescription eyeglass lenses,camera lens, and the computer screen with it.

It's re-washable, costs a only a few bucks and will last me for the rest of my lifetime. Beats the handkerchief or the paper towel. Check it out.