If you like to make your own sauce, you’ll find recipes that tell you how to peel, core, etc. Personally, I like to skip that step and use a device to do that. I have an attachment for my stand mixer that strains out all the skins and seeds and leaves me with the pure juiced, tomatoes.
The first thing I do is wash them and take off the stem. Then, in a big pot on the stove, place a few halves in a bottom layer and cook on low until the juices come out. After that, you can add more tomatoes, a layer at a time until the pot is full. Put the lid on the pot and cook just until the tomatoes are softened. At this point, you can run them through the strainer, manual or electric.
I collect the juice in large pitchers and catch the seeds and stems in a bowl. Then I place the pitchers in the refrigerator overnight and let the solids settle to the bottom. In the morning, I ladle off the top layer of liquid. This tomato water is an intensely flavored and refreshing drink that will revive you on the hottest day of summer. Test me and see if I’m wrong.
The remaining ‘juice’ can be canned as is, or cooked down for tomato sauce and frozen or canned. If you are canning, just make sure you use a safe tested recipe. This website is a guaranteed safe source.
If you are very thrifty or adventurous, spread the skins and seeds that would normally be thrown out onto a sheet tray lined with parchment and dehydrate in your oven on the lowest setting you have. My oven has a dehydrate feature, but if yours doesn’t you have a couple of options. For a gas oven, the pilot light is often enough to dehydrate most things overnight or all day. In an electric oven, you may be able to do the same thing with just the oven light on. You’re looking for a temperature of about 150F.
Once the skins and seeds are dry, they look really gross. Like scabs. That’s how you know they’re done. Sorry. You can grind this up with your spice grinder, that is, a cheap coffee grinder that you use only for spices. It is great for thickening soups and stews and for making dips.
Be thrifty, be healthy, eat well!