The white-powder surface on new sensors this is the non-polarisable electrolytic coating we place on all sensors and it is vital to the functioning of the headset. If you remove it the electrical noise in the signals increases significantly. Please take care never to damage this coating.
It is perfectly normal and not a cosmetic defect in anyway. Please do not attempt to remove this coating as you not only destroy the ability of the headset to function correctly, but you also immediately void the warranty.
It may turn green after exposure to saline but it is still fully functional.