if you prep your wools correctly you will not have any raveling edges...one of the great things about working with wools is- no turn under edges to deal with, no raveling edges- you can use freezer paper to cut out your pieces- don't have to reverse patterns like with fusable applique.
it doesn't matter if i'm using recycled wools or new yardage- the process is the same (after the de-construction step of recycled wools) i wash in washer with HOT, HOT water and detergent- i check it before it gets to the rinse cycle & sometimes reset the wash cycle to wash a bit longer---then rinse in COLD water--then dry in a regular setting/hot dryer- take it out as soon as it's done to avoid over drying/wrinkling- if i do have wrinkles i dampen (or spray with water bottle/steam & iron- but i seldom need to do that. once the wools have been washed & dried you can cut them up and use them for appliques, for hooking rugs, for patchwork...sky is the limit- with no worries about fraying, raveling - you can dye it- sometimes i like to over dye a group of different textures/colors together to create a (family) of textures that all coordinate to use in a project.