Hot-pack method
Wear gloves for hot peppers. Peel and wash onions, then dice into 1/4-inch pieces. Wash and core bell peppers, remove seeds and membranes, and dice into 1/4-inch pieces. Wash and stem hot peppers, retain or remove seeds and membranes as desired, and dice into 1/4-inch pieces. Dip tomatoes in boiling water for 30–60 seconds until skins split, then cool immediately, peel, core, seed and chop into 1/4- to 1/2-inch pieces. Measure the specified vegetable amounts level in dry measuring cups.
Combine the prepared vegetables with commercially bottled lemon or lime juice and salt. Bring to a boil while stirring, then reduce heat and simmer for 3 minutes.
Fill hot half-pint or pint jars with hot salsa, leaving 1/2-inch headspace. Remove air bubbles, adjust headspace, wipe rims, and apply two-piece lids.
Process in a boiling-water canner for 15 minutes at 0–1,000 feet, 20 minutes at 1,001–6,000 feet, or 25 minutes above 6,000 feet. Cool undisturbed for 12 to 24 hours and check seals.