A bra-washing device includes a shell and a divider removably insertable into the shell. The divider keeps one cup of the bra in one location of the shell and the other cup of the bra in another location of the shell. A system for washing garments includes a shell and two or more inserts each interchangeably coupleable to the shell. Each insert includes a three-dimensional form that is different from the three-dimensional form(s) of the other inserts. The openings in the shell may be sized to inhibit a bra strap from extending through the shell through the openings. A device may have buoyancy such that substantially all of the garment is maintained below the surface of water in a washing machine when the device and the garment are placed in the washing machine.