Pu-erh tea

„Nèi piào (内票): A larger description ticket or flyer packaged loose under the wrapper. Both aid in assuring the identity of the cake. It usually indicates factory and brand. As well, many nèi piào contain a summary of the tea factories' history and any additional laudatory statements concerning the tea, from its taste and rarity, to its ability to cure diseases and effect weight loss.“

„The best test is if, when drinking tea, there are any of prickling, tingling, numbing sensations on or near the tip of the tongue. If this is so one can be reasonably certain that agro-chemicals are present.“