So, Here is a photo demonstration of how i save my tomato seeds step-by-step.
Step #1 - Start with ripe, healthy tomatoes
Step #2 - Cut them in half
Step # 3 - Squeeze liquid including seeds, into a jar
Step # 4 - Let ferment for 4-7 days. (pictured bel0w)
Step #5 - Fill the jar containing fermented seeds with water. The seeds will sink to the bottom, and mould float to the top.
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Step #6- Pour off top layer of mould and water. Do not pour out seeds.
Step #7 - Fill Jar with Water again. Let seeds settle.
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Step #8 - You may have to repeat Step #6 & 7 a few times until all that remains is clear water & seeds.
Step # 9 - Strain the Seeds
Step #10 - Let dry on a suspended screen for at least one week
I dry mine of a re-claimed baking rack. It works perfectly!