Hello everybody,
What is the common word to say for students who clean the class by themselves on daily schedule, such as sweeping the class. Is it common to say they do a picket?

I don’t think that is the word you are looking for. A ‘picket’ is something very different. Perhaps you are thinking of the term ‘litter pick’, though this only involves the removal of litter, not sweeping and dusting, and it is an organised event to clean up a specific area. It does not apply to students cleaning the class.
The activity you describe would not take place in the UK.

I see. Thank you so much ma’am for your reply… :slight_smile: