Growing tomatoes, page-24

If you want to collect and use your own tomato seeds this works and gets a far greater sucess rate of germination and better storage. Be aware a lot of seeds from hybred plants you get from supermarkets may never be good plants from seed but heirloom varieties from organic markets can be great.

Clean glass jar is all you need.

Grab some tomato pulp and seeds and put in some water in Jar. Shake the crap out of it and leave it somewhere warm on a windowsill to ferment . Once it has fermented you will see that all the guey clear stuff around the seeds has gone into the ferment . Use a kitchen gauze sieve and rinse with fresh water. Dry seeds on paper towel for a few days . Place in a dark container

If that doesn't make sense have a google and someone will have described it better.