If you're interested, there's a couple ways we can distress and dirty things up without compromising the garment.
The easiest way is to brush on/apply a little Ben Nye's (Clean) Dirt Makeup, it's not permanent and washes off/out. I've got a bunch of this stuff (black, brown and mixed) that I'm not going through as fast I though I would - I can bring some to Tooele.
The other process is more complicated, takes time to prep, apply and dry - its very permanent. It's a standard theater style dirt bath/watered down acrylic paint wash. I've used on a lot of my clothes and even my tent.