When saving tomato seeds, after scooping them out and letting them sit for about a week in their own juices, I will rinse them and put them on either a paper plate or towel to dry on the sink or wherever. That usually takes about another week but sometimes I just forget them for a couple of weeks and they are stuck to the plate/towel...
sometimes, if they still feel slightly moist, I'll just toss them around and leave them for a couple more days. I can tell if they are dry when I toss them - they are light and sound like flakes when they hit the paper plate. Then I put them in a paper envelope ... that way if there is a slight bit more moisture, it won't mold. It's always worked. and then I label them so I'll know what's in there for next year or trading! I've stuck seeds in envelopes before thinking, "Oh I'll remember," oh no I won't
especially these days when I'm saving various kinds!
I have a forum here somewhere about seed saving.... I guess I haven't included tomatoes. I'm gonna add that
thanks for asking!!!