jake, do you mean the streaks? or just the spots?
the streaks i make by thinning out some rust colored paint, usually raw sienna, and i take a very thin brush and just touch it on there where i want the streak.....blow downward on it, or you can also use one of those cans of "duster", i usually use a hair drier......
when i get to the other side of this, ill make sure i take a few pics of my process so you can see what i mean.....
bryan