Master the method to easily dredge

  experience Summary: before using dredge agent, make sure that the less water in the pipeline, the better!
  It is said on the Internet that just pour dredge agent into the pipe. Wrong! Wrong! Wrong!
  If the pipe is full of water, it will react on the top of the water after pouring in Dredge agent.
  Can it be used to dredge the blocked position? Therefore, before using dredge agent, remember to make
  the less water in the pipeline, the better! Remember to use 2 bottle caps (100g) for a few times.