Have you tried the cured shrimp in the tubs cohoangler? There's a reason the same ones ae there from the last time you opened the door on the bait fridge.

There's a way to make them do okay for sometime listed in the Tips section of the site and you can add some plain egg cure to the saltwater and they'll hold even better.

Best thing to do with shrimp? Get some saltwater on top of some good shrimpies and change it every few days - keep them fairly cool ... they'll keep for weeks