Harriet,

Based on the assumption that you made the tomato paste by boiling down tomato juice or stewed tomatoes (the key and essential word here being BOILING) you can proceed as if you were water bath canning stewed tomatoes.

If you have added to the paste any other vegetables or seasoning other than salt or an acidulant you may need to pressure can.

Tomato paste is nothing more than thickened tomato puree. Once you've cooked your tomato puree or sauce down to the consistency you want it, put it into pint jars that have been in the boiling water. Add 1 Tablespoon lemon juice to the jar before adding the hot paste and fill the jar to within 1/2 inch of the jar top. I fill to about where the ring is sticking out on the jar. Put your lids and bands that have been in boiling water on the jars, hand tighten and place in boiling water that covers the jars at least an inch. Boil for 35 minutes remove from the boiling water and and put the jars on the counter and listen for the lids to seal. Wait at least 12 hours and check for seal on lids. Once you're sure they are sealed you can tighten bands and store your paste.

The USDA has several guides to help you with your canning--just click on the links to view/dowload the pdfs.

Here is a link that might be useful: USDA National Center for Home Food Preservation

Harriet, be sure to check GardenWeb's Harvest forum, you'll find all kinds of canning recipes for just about everything.

Mark

Here is a link that might be useful: GardenWeb's Harvest Forum