[Anteater]

The Italians who know a thing or 2 about it always boil their jars of passata and other pasta sauces.

My way to bottle passata (same method for other tomato based sauces, peperonata and  ratatouille) 
http://chat.allotment-garden.org/index.php?topic=82201.msg918774#msg918774

This is a real family event in Italy. The locals use massive industrial sized pans over gas burners and boil their filled jars outside with all the women of the family getting together to help. They also use empty beer bottles, so if you run out of jam jars and can buy metal caps, this works well too.

I just throw mine in the freezer whole, skins and all, when they defrost the skins come off on their own. Fantastic in the winter for soups and stews.