I want to turn these into containers for yarn projects in progress so they can be transported and worked on on-the-go.
Clean boxes inside and out with a VERY slightly dampened cloth or papertowel.
Sand the glossiness off. Wipe off accumulated dust with a Very slightly dampened cloth or paper towel.
Choose a base color and paint. Paint several light coats, allowing each to dry before applying the next coat.
Choose image(s), position and adhere to box. Get as creative as you'd like by adding painted details, beads, buttons, ric rac. You now have a nice storage container. Add a handle and the contents can be easily transported. Line the inside, if desired and the contents will be extra protected.