When processing pine eggs, soda ash, lime, salt and yolk powder are mixed in a certain proportion, plus mud and chaff wrapped around the outside of the duck eggs, and after two weeks, the delicious pine eggs are made.

"The yellow dan powder is lead oxide, which has the effect of making the eggs produce beautiful patterns,"

But with yellow dan powder, the loose eggs will be contaminated with lead. According to national regulations, the lead content per 1000 grams of eggs shall not exceed 3 mg, in line with this standard, also known as lead-free eggs. Therefore, "lead-free eggs" does not mean that no lead, but refers to the lead content is lower than the national standard.