To store grilled corn on the cob, wait until it has cooled completely. Keep the corn in the foil, and then put that foil-wrapped corn on the cob in an air tight ziptop bag in the fridge. The grilled corn on the cob can last five to seven days in the fridge that way. If you really can't finish all your corn in a week, you can always put it in the freezer (although we never have leftover corn last that long).