Describe the grass production process

The picture illustrates the process of producing glasses used for “bia hoi” shops in Viet Nam. Overall, there are approximately ten stages to make a complete glass. Firstly, raw glass is collected into a pile before being broken into tiny pieces. Then such pieces of glass are filtered to remove unnecessary residues. In the next stage, the pure glass fragments are burnt in a furnace in around six hours until they are melted thoroughly. The melted liquid is then poured into a steel mold before it is used to shape a glass by a blowing tube. After it is shaped, the grass’s rim is cut off. Subsequently, it is put in a special gas oven to remain its heat. Next, the grass is taken out from the oven and its shape is refined further with a bottle. Afterwards, the ashes are used to cover the hot grass so its temperature reduces gradually, which prevents any break or crack. Eventually, the grass is delivered to beer shops for usage.