I do the paper bag method, too. They allow seed capsules that may not be quite dry to finish curing. Sometimes if the stems are quite dry and it's a seed that is hard to get out like Salvia or Agastache or Basil, or if it is something with a prickly or irritating seed head like Teasel or Tithonia, I put the stems or seed heads in a large mason jar and shake. The jar offers a little more resistance than the bag. I don't worry too much about what's left behind unless it's scarce, I just scatter what's left for interesting volunteers.
