Preserved duck eggs are a traditional Chinese delicacy, and although known as "1000-year-old eggs" they are rarely more than 100 days old. According to radio-show host Chef Meng, it's a common dish, sometimes known as pidan, that is made by coating duck or chicken eggs in a clay-like plaster of red earth, garden lime, salt, wood ash, and tea. THESE ARE They smell like ammonia. NASTY!!