In a large pot (about 4 litres / US quarts), mix everything from the corn down to and including the vinegar. Bring to a boil, then lower to a simmer and simmer for 10 minutes, stirring occasionally.
Mix the water with the flour or clear jel. Add a few spoonfuls of the hot liquid from the pot, stir that in. Add this mixture to pot and stir well immediately. Let simmer for another 5 minutes, stirring frequently to avoid burning at the bottom of the pot. Don't try to simmer it down to a really thick relish at this point, as it will thicken substantially when it cools anyway.
Put in your choice of the following jar sizes: quarter-litre (1/2 US pint), or half-litre (1 US pint).
Leave 2 cm (1/2 inch) headspace regardless of jar size.
Debubble, adjust headspace with sauce mixture.
Wipe jar rims.
Put lids on.
Process in a water bath or steam canner.
Process either size jar for 15 minutes. Increase time as needed for your altitude.