I actually built this a few years ago and took these studio photos. Then I sort of re-discovered the pics and thought they deserved an airing here. The last model I ever built.
It's A Revell 67 Charger with a few of my experiments in aging and weathering. I think at the time it seemed more interesting and easier than spraying a perfect shiny coat. Apart from the roll bar, everything was out of the box. I'll admit I bottled out of wiring up the engine. The idea was this was an old race car that suffered a few battle scars, then was put out to grass when it became un-competitive. The dust is a bit of natural patina to add to the fake stuff.
In this case my patina technique was first spray all over in red oxide primer. Then paint over with modeler's acrylics thinned down so the paint flows smoothly. Two or Three coats should do it. Then start rubbing with the wet and dry so the primer shows through. The mud and mildew and streaks of dirt are acrylic paints again, brushed on. The dirt on the underside is real garden dirt mixed in with the paint.