Inexpensive bags of granules can perfectly clean the cork, but having caustic soda in its composition there is a risk of damaging the pipe with such chemistry. To prevent this from happening, the granules poured into the siphon cannot be poured with boiling water. The fact is that during the reaction of "caustic soda" additional heat is released. Which, when combined with boiling water, can damage the pipe or siphon. Therefore, we read the instructions and do not pour boiling water into chemicals.