When i got my car, all four headlights were so cloudy it would never be safe to use in the dark let alone pass any MOT. I did this...http://www.youtube.com/watch?v=Wo6KnlZnFAw It actually works really well. T cut will have no effect on cloudy headlights because that is the first thing i tried. I wish i had taken before and after pics because mine were really bad to the point i almost changed them altogether.