Sometimes my classroom can be a total mess at the end of the day. Especially if the scissors come out. Sometimes I just feel so embarrassed when the janitors come in so I try to make it looks as clean as possible.
I saw this idea somewhere last year, tried it and it worked so well.
At the end of the day when we are doing dismissal procedures, I secretly pick a piece of trash on the floor. Then I tell my class that whoever picks up the magic piece of trash gets a prize. (I use a piece of gum.)
Those who want to participate, usually most of the class, quickly get up and pick up every piece of trash in the room.
This works perfectly because if I wanted to reward someone who usually doesn't get rewards, no one has to know which piece of trash I really picked.
If I were a better teacher, I might be able to get students to pick up trash just because it is there. But that is an improvement I'll focus on further in my teaching career.