In one example in accordance with the present disclosure, a fluid extraction system is described. The fluid extraction system includes an interface to fluidically and electrically couple a removable extraction reservoir to a printing device. A supply line of the fluid extraction system transports fluid from the interface to a reservoir of the printing device. A return line of the fluid extraction system is coupled to the reservoir and supply line and transports fluid from the reservoir to the interface. The fluid extraction system also includes a switch to, responsive to removal of the removable extraction reservoir from the printing device, activate a fill pump to draw fluid through the supply line away from the interface.