Easiest way to weather it. Take it out to a dirt field on a really dusty/dry day. Run it for a good while. Then take it out to the same field on a drizzly day. Not rainy downpour. Just a drizzle. Drive it around until theres an even sheen of wet al over it. Let it dry to see the results. Repeat often if necessary...or fun. Basicall let the elements and weather well....weather it. Sun to fade it, dust to dirty it and mud to finish off the effect.