Windex should remove it well enough. Just be sure the enclosure is completely empty and you rinse it well and let it dry. Maybe use a distilled water/vinnegar solution after as well and rinse that out. I have hard spots on mine from using bottled spring water and got most of them off with just dish soap and water with thourough rinsing afterwards but still have trace amounts of the spots. I don't care too much so I just left it. The enclosure looks fine enough for me but if it's bothering you enough that's what i'd recommend.