This is a canned recipe so if you have never canned before read up on it in the Joy of Cooking or this great new book I found on canning called Canning and Preserving with Ashley English. She has a whole section on pickling.
Green Tomato Pickles
1 dry quart of green tomatoes (This is what will fit in half a peck basket or about 1/6 more than a liquid quart by measure.)
2 large onions
1/3 cup plus 1 1/2 teaspoons salt
3 cups vinegar
3 red peppers, seeded and chopped
3 green peppers, seeded and chopped
3 cloves garlic, chopped, not pressed
1 1/2 tsp. dry mustard seeds
1 1/2 tsp. whole cloves
1 Tbls. ground ginger
1 1/2 tsp. celery seed
(I use 3 Tbls. of Backyard Patch Pickling Spice instead of these spices to make mine)
Slice the green tomatoes and onions thinly. Sprinkle with 1/2 cup of salt and let stand overnight. This removes the excess water and is important to the preserving process so do not skip this step. Rinse and drain in the morning.
Bring the vinegar to a boil and add the peppers and garlic and boil vigorously for 1 minute. Add the tomatoes, onions and spices and simmer slowly for 20 minutes. Pack while still hot into sterilized canning jars and seal immediately with hot sterilized caps. Then process in a hot-water bath for 5 to 7 minutes. Makes 5 to 6 pints of pickled tomatoes.