Since the metal mould has many tiny small holes for steam to pass through in order to soften the crispy dry tea leaves before compression, there will be a lot of nails left behind after the strong compression.

• 由于铁模上面有许多小孔，用意是给蒸茶的蒸气通过，好使乾脆的茶叶软化，因此蒸压之后就留有乳钉。