I keep our classroom brushes on top of the cabinet next to the sink. The cans are held by a 3 inch deep box lid which helps keep the brush storage area organized. We separate the brushes according to the bristle size and type of handle. All the tall easel brushes are in one can. The wide, flat brushes are in a different can. We have three cans that hold smaller, detail brushes.
When children are painting with watercolor paint they are responsible for rinsing out brushes and returning them to the can at the end of class. Notice that the brushes are stored with the bristles upright. I teach my classes to put them back with the "hair in the air". The little rhyme seems to help.
If tempera paint was the chosen media, then I have brushes collected in a soapy water bucket so that they have time to soak and I wash them myself.