Keeping dustcover looking new

Just bought a new dustcover for my TT ,love the clean,shiny, no swirl-mark look. Any tips on keeping plexiglass looking good?. In the past I would lightly dust with Windex,but over time the hazy swirl marks inevitably appear. What do you recommend to protect a new DC? Ive heard car wax, Armorall, rain-x, etc. Any ones experience is appreciated.