It depends on where you get your outside branches. If they are coming from your own trees then cut them down to size. Just check for any type of sap or bug infestation. Remove any loose or excess bark that your chameleon might be able to injest.Grind off any shap edges or nubs that might stick out and injure your chameleon. They should be smooth. If they are coming from a neighbor's yard or area where it is unknown to you about pesticide spray, then I would wash with soap and water and let dry. Some people bake them(if you can fit them in the oven). I for one think this is a waste of time. Just my opinion. I get mine from my front tree. My branches are nice and smooth so I cut them grind off anything sharp sticking out and I am good to go!