I am not a janitor, but a teacher. Most of my kids are cleanly. However, it only takes a few to make my room a mess. I will list what I see mostly. Cut up pieces of paper on the ground, broken pencils, food wrappers, crushed up chips, broken protractors, etc. It's sad to see how little some of my kids care about cleanliness and taking care of equipment. If my room is a mess, I make the kids clean it up. I always tell them to be mindful that someone has to clean up after you and that we are not going to make their job harder. I always have that kid that says, "But it's his job!" That infuriates me. You are still cleaning up afterself little Johnny Shitstain.