I give a 10 minute warning, a 5 minute warning. Then I say, Thumbs-up...and
give a three step direction for clean up (usually where to put work,
supplies, etc.) I call students by table so not everyone is doing everything
at the same time. It is still chaotic, but usually somewhat organized. I
also tell the students do their own things first, then help their table, then
do the room (usually the floor or someone who is lagging behind).