However, filtration with active charcoal itself is now a technique of the past, and recently the amount of active charcoal used, the frequency with which it is used, and the number of charcoal specialists (known as sumiya) have been on the decline.
活性炭濾過そのものが過去の手法になりつつあり、現在では活性炭の使用量、使用の有無、炭屋なる専門職は減少傾向にある。