How do you bring the plastic in the engine compartment back to life. I have cleaned it and dressed it before but it seems to become dull and ashey lookin pretty quickly. Does anyone know of a product that will put the shine back into old plastic, or is there a process I should be doing to achieve that new plastic look. I look at some car shows and the plastic throughout the vehicules is always imaculate as if brand new. Any tipps greatly appreciated!