1. plant ash method: for every 50 fresh eggs, use 5 ounces of alkali, 0.5 ounces of black tea powder, 2 ounces of salt, 3-4 ounces of quicklime, 2 kilograms of boiled water, and about 65,438 kilograms of plant ash. The preparation method is as follows: first, put black tea powder, alkali, salt and lime into a jar, and then add 2 kg of boiling water. After the lime is completely melted, stir it evenly, and then slowly add plant ash, stirring while adding it until it becomes paste and wrapped. Then, wrap the fresh eggs with packaging materials for 2 minutes, cover them with bran, and seal them in a jar. After 7 days, turn the eggs in the jar up and down once, then seal them and put them in the shade. One month in summer and about two months in other three seasons, you can eat it. The temperature must be kept above 15℃ in winter.

2. Simple method: For every 50 fresh eggs, use 0.5 taels of salt, 2.5 taels of alkali, 0.5 taels of tea, 5 drops of lemon oil, 5 drops of peppermint oil and 5 kg of water. Preparation method: Wash eggs, filter with tea soup, and add mixed solution of water, alkali, salt, lemon oil and peppermint oil. After the immersion liquid is cooled, the eggs are soaked and sealed for more than ten days in summer to make them solidify. It takes a little longer to soak in winter. If you want to make the eggs look good, you can add a little alumina after the immersion liquid cools. After the preserved eggs are done, take them out to dry and wrap them in wax paper for preservation.

3. Soda soaking method: prepare 5% sodium hydroxide solution with caustic soda and water, and then add 4% salt, 2% tea powder and 0.2% alumina to prepare soaking solution. Then put the washed fresh eggs in, leave them at room temperature of 25℃ for 28 days, then pour out the soaking solution, seal the container and take them out after 24 or 5 days.