The storage containers of the 21st century are presentable enough to set in rows on the floor or on shelves, and portable enough for a child to move them from room to room or for a parent to set them out of reach or out of sight.

Clear or opaque plastic suitcases or bins with handles and lockable lids store paints, clay, and other messy stuff. Fold-up storage boxes move easily not only from room to room but also from home to grandma's; they're great for travel storage and take up little space when not in use.

Wide, flat boxes slide under a bed or dresser — perfect for putting away dress-up items, board games, and big blocks. Crayons, colored pencils, and other nonmessy art supplies can be kept in a tool box or fishing-tackle box near paper and coloring books.

Folding mesh cubes, $4-$12, www.containerstore.com.

Translucent totes with handle, $9-$13, www.containerstore.com.