Making ketchup
I copied this one from the Bernardin website as it's the same one I use. They recommend using your home canned products within a year but in reality they will last much longer.
A "canner"is SIMPLY A LARGE POT with a lid. You must have a rack in the bottom so the jars do not sit directly on the bottom of the pot. You can make one out of canning rings tied together with twist ties if you don't have one.
Of course you could cut the recipe in quarters and only make a small batch and eat it right away but I figure if I'm going to make a mess I may as well make it worthwhile!

Makes about 7 x 500 ml jars.

24 lb (11 kg) tomatoes, about 96 medium sized
3 cups (750 ml) chopped onions
1 (5 ml) tsp cayenne pepper
4 tsp (20 ml) whole cloves
8 inch (20 cm) cinnamon stick, crushed
1 1/2 tsp (7 ml) whole allspice berries
3 tbsp (45 ml) celery seed
3 cups (750 ml) apple cider vinegar
1- 1/2 cup (375 ml) granulated sugar
1/4 cup (50 ml) pickling salt

• Place 7 clean 500 ml mason jars on a rack in a boiling water canner; cover jars with water and heat to a simmer (180°F/82°C). Set screw bands aside; heat SNAP LID® sealing discs in hot water, NOT boiling (180°F/82°C). Keep jars and sealing discs hot until ready to use.
• Wash and quarter tomatoes. Combine tomatoes, onion, and cayenne pepper in a large stainless steel saucepan. Bring to a boil; reduce heat and simmer 20 minutes, uncovered.
• Tie cloves, cinnamon, allspice and celery seed in a large square of cheesecloth, creating a spice bag. Combine spice bag and vinegar in another large stainless steel saucepan. Bring to a boil; turn off heat and let stand.
• When tomato mixture has cooked 20 minutes, remove spice bag from the vinegar. Add vinegar to tomato mixture; boil 30 minutes.
• Press tomato mixture through a fine sieve or food mill and return to saucepan. Add sugar and salt. Stirring frequently, boil gently until volume is reduced by half, or until mixture mounds on spoon.
• Ladle ketchup into a hot jar to within 1/2 inch (1 cm) of top of jar (headspace). Using nonmetallic utensil, remove air bubbles and adjust headspace, if required, by adding more ketchup. Wipe jar rim removing any food residue. Centre hot sealing disc on clean jar rim. Screw band down until resistance is met, then increase to fingertip tight. Return filled jar to rack in canner. Repeat for remaining ketchup.
• When canner is filled, ensure that all jars are covered by at least one inch (2.5 cm) of water. Cover canner and bring water to full rolling boil before starting to count processing time. At altitudes up to 1000 ft (305 m), process –boil filled jars – 15 minutes.*
• When processing time is complete, remove canner lid, wait 5 minutes, then remove jars without tilting and place them upright on a protected work surface. Cool upright, undisturbed 24 hours; DO NOT RETIGHTEN screw bands.
• After cooling check jar seals. Sealed discs curve downward and do not move when pressed. Remove screw bands; wipe and dry bands and jars. Store screw bands separately or replace loosely on jars, as desired. Label and store jars in a cool, dark place. For best quality, use home canned foods within one year.