|A mate of mine came up with what I thought was an excellent plan to keep bait fresh for longer on a fishing outing. He cut a piece of polystyrene so that it fits snugly into his cooler box. He then glued a piece of board ( plastic might be better) to the top and fitted a handle. What he now does is split his bait into 2, what he plans to use first and then all the extra "in case" bait we always seem to cart along. The extra bait goes in first, then the polystyrene lid and then all the stuff he plans to use first. So every time he opens his bait box the bottom layer stays cold. He no longer has to throw away unused bait just because it has defrosted and gone pap.
Sorry i don't have a picture but it's a fairly simple concept. ( i'm sure many are doing it already)