I leave it on. Removing them would be way too much work.

Rhonda

I collected 4 species of Asters this fall - Symphyotrichum cordifolium (blue wood), laeve (smooth blue), novae-angliae (New england), and oblongifolium (Aromatic). The seeds form in a similar way for all these.

I let the seedheads dry in paper lunch bags for several weeks. When they were fully dried and kind of fluffed out, they seemed ready. I would pinch the whole seedhead tight and pull it off the stem. You can see the clump of seeds at the bottom. Holding the whole thing tight, I would brush the seeds off the seedhead with my other hand. They would fall off leaving most of the chafe behind. Worked pretty well. Now I hope my seeds will sprout next year! :)