Wash the tomatoes well

Remove the stem, and trim out the core

Remove any bad spots, if needed

Cut into halves or quarters as needed - you want pieces no bigger than 2 inches square or so.

When the food processor is 3 quarters full, pulse several time to get it going, and then process until the tomatoes are liquified - about 20 to 30 seconds.

Carefully empty the resulting puree into the food mill, which you have set over a bowl the correct size to hold it securely, and run through the mill to remove the seeds and skin.

Empty the sauce into a large stock or soup pot, and set the heat on medium to get it going as you process subsequent batches of tomatoes. You will want to scrape the seeds out of the food mill every so often to keep it working efficiently.

Repeat the above steps until you have gotten all of the tomatoes done.

Cook the sauce uncovered until it is the thickness you are looking for. I use a spatter guard to keep things neater, because it is pretty likely to spatter some as it gets thicker.

You can add salt to taste if you like, but it's not necessary at this point, as you can salt the dish you use it in later on.

If not all of the puree will fit in the pan at first, it can added as the sauce cooks down.

This sauce can be canned [see post for links to safe canning practices] or frozen in containers.

An 8 quart stock pot, filled to within an inch of the top will yield about 5 quarts of medium body sauce.