well, not really their job at least.
So here I am in my room at school, watching over the kids who can't seem to control themselves. They make a mess of this room and from time to time, leave a mess for the custodian to clean up. Just today, I had a student who left decent sized pile of pencil pieces on the floor. He refused to pick it up. I told him its not the custodians job to pick up his crap.
Well jeesh, that started a discussion that sort of I can't win.
While custodians jobs are to clean things and make the rooms ready for the next day (as far as clean floors, desks, sinks, towels and like supplies), they shouldn't have to pick up crap that students purposly leave behind.
In Las Vegas, when I taught both 4th grade and kindergarten, I made my students clean up the room. I made a game out of it..sort of like a scavenger hunt (called Mystery Item...look for the mystery item and if you find it...you win a prize!). It was designed to get the students to pick up their mess so the custodian wouldnt have to spend extra time doing so. When I taught Kindergarten...I did the same thing for my Kindergarteners...and they had a blast as they got a sticker for finding the item. Then they stacked the chairs themselves into stacks of 4. Everything in the room was clean so that when the custodian came in...all he would have to do is empty the garbage, vacuum and mop.
I think students should learn some responsibilty in picking up their own mess instead of leaving it for someone else to take care of.