Hi @Bill9 - Thanks for reaching out! Washing a backpack in a washing machine is not recommend.
We suggest using lukewarm water, a sponge, and some mild soap. If you have a bathtub available, it might be easiest to wash it there to contain the water and slime mess. For more details on the cleaning process, you can take a look at our Expert Advice article How to Wash a Backpack.
Hopefully this helps!