restore faded plastic

Buy the small buffing wheels, a number 36 and a number 60 or finer and a stick of plastic buffing compound at a hardware store.. Mount the wheels on arbors and chuck up to a drill motor. Use the 36 wheel first and run over th item( don't apply to much pressure as you might harm the item, of course apply the compound to the buffing wheel) . Use the buffing wheel just like using  the buffer when waxing a car. When the item clears switch to the number 60 wheel (compound applied) and buff again untill the headlight, trim, is clear and shines. A very light touch moving the wheel back and forth  only ( like fine sanding wood ) and at a high speed near the finish  gives a better appearence. Practice on some old part to perfect your skills. The results will last for years.