one method I've heard of is using a coffee filter instead of paper towels, the
seeds come off easily...the traditional method is to put enough
seed into a small cup or container, and only add liquid if needed, and stirring is not necessary, wait until some white mold forms on the surface, then strain the juice off and scrub the remaining gel off of the
seed, the fermintation takes care of almost all residual disease spores or bacteria, and makes the gel coat easier to remove. There are many
seed savers who simply scrub the
seed with TSP, (a mild chemical cleaner,) and/or use a dillute bleach solution to kill bacteria/virus pathogens. Some even use Comet cleanser as a one step scrub and sterilizer, it can be as simple as that.
The thing to keep in mind when saving
seed, is that hybrids are more likely to come back as something other than the tomato you save
seed from, than the tomato you buy. OP's, open pollenated, tomatoes, should come back true to the named variety, and suzydaze mention of Brandywine and Arkansas Traveler are among my top 3, or 2, and those are open pollenated, so saving
seed should be almost foolproof for coming true from saved
seed, but keep in mind that days to maturity and production are affected by climate, so do a little research into your average last and first frost dates for your area, and keep in mind that most tomatoes pollenate and produce better in longer seasons with highs under 90 or so, and that in general, the wonderful Brandywine produces less in most cases than many varieties.