If you want to cover Niulanshan No.1 back, you can insert a knife or a sharp piece in the position of the plastic barb and pry it out a little bit to deform the plastic. There are eight barbs in a circle. You must pry it open and pull it out. You can put it back, but you can't fully recover it. There are barbs between the white plastic cover on the bottle body and the porcelain bottle mouth (the porcelain bottle mouth has a circle of grooves). Just want the bottle, pull out a layer of plastic retainer on the outside of the bottle cap, and cut off the next circle of the white plastic cover to take it off.