Usually yes. Check the cleaning instructions for your heated blanket. There should be a care label stating the washing temperature. However, it must be possible to remove the controller. Most come with detachable controllers, enabling you to unclip the cord before loading it into the machine. However – never use the spin cycle. Spin drying an electric blanket can put excessive stress on the wiring – generating faults that might only appear when you use it. Bent wires generate heat and can cause short circuits.