I agree with Lisa. Just let them know that the seeds will include chaff. I don't clean all my seeds. I let them dry in paper bags, shake, remove as much of the big stuff as I can and then package the rest. Even if I question the viability of the seeds, I'll include that in the communications during the arranging of the trade. Last year I had seed heads of Achillea Cerise Queen which Stage Rat wanted so I let her know that I didn't know if there were even seeds in there since I didn't know what they looked like and it didn't look like the pods had matured. None came up, but it was more or less expected. This year the plants are producing mature seeds which I can see so I'll send her some more and we'll see if these are viable. As long as the recipient knows where they stand...

I grow Coreopsis Domino which I truly like. A nice bushy plant with loads of yellow blooms with a red center. I tried something different though and chopped them down a bit in early June. The four plants I did this to stayed nice and compact and didn't flop. Still bloomed like the dickens!! I'll be doing this from now on with them. :O)