As far as I know it is the sap from the branches and stems that is toxic, and that it is perfectly normal for the chams to eat a few leaves now and then. It is when you trim the plant (i.e., cut down the branches and stems) that you need to remove the plant and let the sap dry before returning it to the cage. I'm not a horticulturalist, but apparently the fluid in the leaves is different from the fluid in the stems. Like tomatoes- you can eat the fruit but the stems are toxic to many species. And rhubarb- you can eat the flesh (which is actually the stem or branch) but the leaves are toxic. A couple of our chams frequently eat schefflera and it seems to do them good.