Scott,
While a q-tip will work, a better tool is a small paint brush, such as a watercolor brush. Give the brush a dip in vegetable oil-not too heavy, just to give it some tackiness-and mop up the pollen in the umbrella. You will see it clearly on the brush. Now, rub the brush across the surface of the little nubs near the tips of the umbrella points to wipe off the pollen. Repeat the process the next day, and even a third day if you want lots of seed in fall.
Doing this on the same flower will result in a selfing. Mopping up the pollen on one flower, and then rubbing the nubs on the flower of another Sarr will result in cross pollination. As a kind of generalization, selfings don't always work with S. minor and S. flava.