Starting with fresh herring; usually I jig my own, I have had the best luck plug cutting them immediately and placing in a cold brine (salt, powdered milk and bluing) for up to 6 hours (I use frozen sea water to cool the brine). If you have the space it works well to keep the brine and herring in the freezer; a strong brine will not freeze in the normal home freezer.

However usually I have limited space so I remove the cut plugs from the brine and roll them in borax (the same I used to use for curing eggs). I put the boraxed cut plugs in freezer bags with extra borax. I usually put a dozen/bag. Have had good luck I keeping boraxed for up to month and have found they fish very well; typically the borax cut plugs fish with freshly jigged bait fish for fish.

If on a fishing trip the cut plugs treated with borax will keep and fish well for several days without freezing.

Curt