The first step to washing a pet sleeping bag is to consult the instructions on the label or on the manufacturer’s website. If the option is machine washable then use a gentle cycle with the temperature required by the bag maker.
Make sure that you put it through a second rinse cycle to remove all of the cleaning products out of the fabrics. Next, squeeze the excess water out of the bag and place it in a commercial-size dryer on low heat.
For hand-washing the bag you should avoid using too much soap and rub together the most heavily soiled areas and allow them to soak for up to one hour. Then you should drain the tub and fill it with water to rinse it until all the soap is gone.
If you don’t have a dryer, you can place the bag flat on a clean surface or hang it in an area with low humidity and no direct sunrise until it is dry.