Adults and children use backpacks for convenience transporting books and essential needs. So it makes sense that they get dirty quickly. You should always hand wash your backpack so it will retain its shape. Make sure you open all pockets and zipper and shake out all the crumbs. Brush or vacuum out any loose dirt. Dip a cloth or sponge into a mixture of warm water and dish soap to clean the interior. Use the same solution for the exterior. Scrub any stains and especially the straps. Then, swish the backpack in a sink or tub that has been filled with cool water to rinse well. Squeeze gently and blot with a towel to remove excess water. Hang upside down away from heat and  sunlight to dry. Nice and clean!