How much to weather a model is really one of personal preference.  I like matt finishes on models but will also go for a sheen if the automobile is newer, like this 1941 Nash.  I avoid a high gloss finish on a car or truck as it looks toy-like. I also prefer light weathering generally, although some vehicles can be quite dirty too.

On light colored vehicles, I’ll apply an oil wash using Abteilung 502 ABT005 Smoke:

I apply a light (not drenched) very thinned mixture overall, like seen in between the dimples on the pallet above. Then, I use a fine tipped brush to apply a stronger amount into the model detail recesses (body exterior, wheels, and cabin area). The first wash wicks the stronger wash into and around the detail. I will also apply a wash of Abteilung 502 ABT130 Dark Mud mixed with ABT125 Light Mud to the underside of the chassis.

For a dark colored vehicle, I’ll just dry brush Tamiya XF-57 Buff over the raised details (see Category: TIPS-MODELING/DRY BRUSHING). I may also airbrush this same color (very thinned) for a dusty effect.

Once the oil wash is dry, I very lightly dry brush the interior and under chassis with Tamiya XF-57 Buff. The tire treads can be dry brushed either grey or buff.

When the weathering is done, the windows are made using Elmer’s Clear School Glue (see Category: TIPS-TOOLS/ELMER’S CLEAR SCHOOL GLUE). After leaving the windows to dry overnight, the body is CA’d to the chassis.

A satisfying bite-sized project.