The night before I either use Sea water or a tub of ice, add rock salt, I guess as to the amount (if your hands sting when you reach in that's a decent amount ), and then the frozen herring. If I am not going to fish again for a few days I zip lock the herring and freeze it again but only for herring strips. I don't use the re-frozen for cut plugs although you probably can. If you thaw it first remember to punch some holes in the bag or it won't thaw well.