This article is from the Food Preserving FAQ, by Eric Decker firstname.lastname@example.org with numerous contributions by others.
10 C chopped, ripe tomatoes 2 C sugar
2/3 C chopped green peppers 2 C 5% acid cider vinegar
2 C chopped onions 2 T canning/pickling salt
Dip tomatoes into boiling water 1/2 min. to loosen skins. Cool in cold
water. Remove skins and cores. Blend or put through food chopper. Place
in 8-qt. kettle. Remove stems, membranes and seeds from peppers and peel
onions before chopping. Add to tomatoes; stir in sugar, vinegar and salt.
Simmer, uncovered, stirring frequently, for 2 hours or until thick and sauce
begins to round up on spoon. Ladle into 3 hot pint jars, filling to within
1/8" of jar top. Wipe jar rims: adjust lids. Process in boiling water bath
15 minutes. Start to count processing time when water in canner returns to
boiling. Remove jars and complete seals unless closures are self-sealing
type. Makes 3 pints.