When I left my sensei to begin teaching, she gave me a list of guidelines to help me set up my own school. One of the most important was the mizuya (preparation room) guidelines:
In the preparation room silence is the rule. Idle chatter is distracting. Clean utensils immediately and maintain the mizuya in a state of readiness. Never leave personal items in the mizuya. At the end of class, ready utensils for the next day’s activities.
And Sensei says: the mizuya should be kept clean and orderly at all times. No excuses. Often the preparation room is a small confined space that people need to share and work efficiently in. The tea house in Seattle has a small, sit down mizuya that is only one mat (3 feet by six feet). If everyone is working together and efficient, then 3 people can work in this space and produce a hundred bowls of tea.
It is very tempting to hang out in the mizuya because that is where a lot of the action is before and after class. But loiterers get in the way and working around someone who just chatting interrupts the work flow and is distracting. I don't know how many times I have been kicked out of the mizuya by the cho (head of the mizuya) for chatting more than working. My sempai once told me that if he didn't see my hands working more than my mouth I was to take myself out until I could control myself.
When I was the cho, I myself have kicked people out of the mizuya. If you are not working, get out of the mizuya. It is a place to work, not socialize.
If you first come to class and see that there are things to be cleaned, just do it. It doesn't matter if you made the mess or if it someone else's responsibility. If you see it, it is assumed that YOU are responsible. Clean it up immediately.
After your lesson, you MUST clean up all of your utensils immediately after the aisatsu (thanking the sensei for the lesson). Rinse your bowl and put away, clean your chasen, rinse all the tea off your chakin. Clean the stickiness off any sweets tray, wipe the chashaku with a tissue, and refill the natsume for the next student. Put away all of your utensils in their proper places.
When class is finished, everyone helps to clean up. If there is no cho assigned, the most experienced student becomes the cho and must ensure that all of the cleaning is done properly, and utensils put in their proper place. If there are less experienced students hanging about not knowing what to do, it is your responsibility to show them the proper way to clean, prepare and work in the mizuya. Notice I said show them, not tell them.
" In the preparation room off the Totsutotsusai tea room at Urasenke in Kyoto there hangs a plaque in the hand of the thirteenth generation Grand Tea Master, Ennosai, listing the rules for the mizuya. In addition to a chart showing the storage places for the utensils, there is written: 'This is a training ground for the tea room . Recently it has not been kept in order and has become quite unsightly. I have drawn a chart; henceforth, people who finish practicing must place all utensils back where they found them.' Precisely because the preparation room is not seen by the guests, it must be kept cleaner than the tea room itself." ~ from The Spririt of Tea by Sen Soshitsu XV.