Tea sets that are used for a long time without proper cleaning will develop tea stains on the inner walls. These stains contain various metal substances such as cadmium, lead, iron, arsenic, and mercury. When drinking tea, these harmful substances enter the body with the water and combine with nutrients like proteins, fats, and vitamins from food, forming difficult-to-dissolve compounds that hinder nutrient absorption. Simultaneously, these substances can cause lesions and functional disorders in the nervous, digestive, urinary, and hematopoietic systems within the body, ultimately endangering overall health.

Therefore, it is essential to regularly clean the tea stains from tea sets to prevent negative health impacts.