Preserved eggs are made of lime (calcium hydroxide) and washed alkali (sodium carbonate) mixed in mud. In order to speed up the production cycle, a certain amount of lead oxide (Lithuanian) is often added. Therefore, preserved eggs not only contain a lot of lead, but also are alkaline (alkalinity is sodium hydroxide generated by lime and alkali washing). Eating preserved eggs not only consumes a lot of stomach acid, but also consumes more lead, which is not good for your health. Even if you want to eat, it is best to eat lead-free preserved eggs, but it will still consume a lot of stomach acid, so it is better not to eat them.