We felt bad about throwing away all the skins and seeds accumulated when making salsa and stewed tomatoes. This lead to some research, and a bonus canned good: tomato paste. Not only does making tomato paste make you feel better about not wasting food, it is super easy and tastes amazing.
You can save your skins, seeds, etc and freeze them until you have enough to make a batch.
Take all the tomato skins and seeds and put them in a pot.
Simmer until thickened, it will start to look like tomato paste with seeds and skins mixed in.
Pour all contents into a metal strainer over a bowl, using a wooden spoon to push as much of the paste through as possible
You will be left with seeds and some rolled up skins in the strainer, and a feeling of satisfaction that you significantly reduced what you are throwing away.
In the bowl will be your tomato paste. If you feel it isn’t thick enough yet, return to the pot (after you rinse it out) and simmer until the right consistency.
The final step is to add about 1 tbs lemon juice per pint; you are ready to can and enjoy.