making the kids work for their food is a good idea. Instill values of hard work, but don't humiliate them. Problem is, it's hard to achieve in practice. And I can imagine the rich kids sneering at the poor kids doing the cleaning up. That doesn't make for a friendly, healthy, balanced school environment.
One way to do this could be to have a school duty roster where everyone pitches in to help clean the school. INCLUDING THE RICH KIDS. The difference is that if you're on free lunches, you have many more spots on the roster. If you have a disciplinary problem, you also have more spots. But everyone gets his hands dirty at least once a month.
In any case in many Asian schools it's normal for schoolkids to clean the classroom as part of their routines. It's Americans who are not used to having such basic civic things like responsibility for one's environment drilled into them. I remember my first year in an American college, and I was really shocked at how filthy and disgusting Americans were in private life. Some did not throw out the trash ALL SEMESTER, accumulating literally an entire closet filled with pizza crusts and food boxes. Others did not do laundry a single time, and got their mom's station wagon to take back 4 freaking months of dirty laundry in one shot. One guy bought a huge box of utensils from costco or sam's place, can't remember which one. He never did any washing, and threw away METAL FORKS AND KNIVES after every meal.
My second year in college, I was praying for thanksgiving. You know why? Because at thanksgiving, my fat American roommate would take home his unwashed laundry! After thanksgiving things get better because it's cold enough for the laundry to not stink, until spring came by again and the usual stench filled the air.