Cover the shallots with brine (made with 2 cups salt to 1½ quarts water) and leave to soak in a plastic, glass or china container for a week in the fridge.
Now you know how much liquid it takes to cover your shallots, heat the same amount of a mixture of half and half malt vinegar and white wine vinegar in a stainless-steel pan with the collection of spices. While this comes up to the simmer, rinse the shallots thoroughly and then place into the simmering spiced vinegar for 5 minutes then remove from the heat and bottle in clean, sterilized sealable jars and keep for a month somewhere cool. They are now ready to use. The leftover spiced vinegar is very good for dipping cooked whelks in.