I am not sure if the remaining goo would be a problem, but if you want to be sure you are donating good seeds, try a germination test on 10 or 20 seeds. Some people do germination tests by layering the seeds in a moist paper towel inside a plastic baggie. I do mine in a flat tupperware by laying a couple paper towels on the bottom of the container, then spreading out the seeds, mist them to keep moist, and lightly cover. Tomato seeds will sprout within a week or so if kept moist in a warm dry spot.

Thanks Terrene - the seeds look like ones "from a package" now. I will let them dry a couple of weeks and then do the germination test to see how they are before I donate them back to the seed library. Great idea - thanks!

I have had a little stubborn goo left on some of mine, too, but they seem to dry down OK on paper plates.

I've always noticed that if they look 'hairy' and furry, after dried, you've come away with very healthy seeds that are extremely viable.