I use Turtle Wax ICE with a sponge applicator and a synthetic polishing cloth - the finish is fantastic and you can use it on plastic as well as metal - it does not leave white streaks. You can also polish the whole car in one go. Despite what it 'says on the tin' I wouldn't polish the car if hot or in sunshine. I also use the Turtle ICE wax-wash between polishes and this revives the shine (not that it needs much reviving) but needs to be rinsed before it dries.