Wash fresh duck eggs in water and brush with running water. Clean the surface of the duck egg with a scouring pad or brush. (Note that duck eggs should not be soaked in raw water for too long)
Dry the washed duck eggs by kitchen paper or a clean cotton cloth and leave them in a cool, ventilated place for a while. (Or you also can let them sunbathe for 3-4 hours in the early morning sun.)
Add 2L of water and 400g salt in a wok and heat it until boiling. Set aside and cool it.
Add the white wine in a bowl. Put the duck eggs in the bowl and make each duck egg wrap a layer of white wine or you can also spray the white wine directly onto the surface of the duck egg, and then put it into the jar. (In the end, use a heavy object on the top of the duck eggs to prevent duck eggs floating on the saltwater), pour the salt water.
Close the lid and affix the date. Leave it in a cool dark place and marinate it for 32 days. Cured eggs can be stored in the refrigerator for up to two weeks.