I've used leaflitter in the past with snakes and Megophrys frogs with good succes. For sterilising I boil the leafs for 30 minutes. The rest is like Grif described. I only use oak leafs, preferably collected in the fall. I read somewhere that Magnolia could be toxic but can't find the sourse at the moment. An alternative to collected leaflitter are Catalpa leafs. These are sold at pet & fish stores for raising softwater shrimp. a bit expensive but worth it. Catalpa is a native tree to the rainforrest of South America and one of the main food of Iguana iguana, aka the green iguana. This is also one of the main food items given to iguana's on the farms where they are raised commercialy. I'm sure they would be perfect. I'm expecting some large import cornuta's from Surinam in a few weeks and am going to put them on these leafs so they can settle in. I will keep you posted. In the mean time take a look at this clip of C. cornuta in nature.