You'll have a hard time getting to those ninja monkeys if you dont have any other greegree in your bank. What I did when I had to get my greegrees back: Teleport to Ape Atoll, kill a gorilla. Use the glider from the Grand Tree to get to the other side of the island, where you can enter the tunnels and make the gorilla remains into a greegree (While you're there, kill a zombie monkey and make those remains into a greegree too) Then, teleport back to Ape Atoll, and go into the building with the light floor and the cellar. Make sure you are standing in the dark area and remove your greegree. Step into the light, and immediately step behind the crates/ladder. Two ninja monkeys will appear, and they will send you to jail if you dont hide in time. A ninjagnome will appear and kill the monkeys for you. Equip your gorilla or zombie greegree and pick up those remains. Run to the tunnels/Zooknock, and make those remains into greegrees. Alternatively, instead of making a gorilla greegree first, you can go to Karamja, kill a monkey there, and make those remains into a greegre.