Gather up the amount of items you want, it can be anything! Iron, Gold, Diamond, Arrows etc!
1. Make ALOT of Ladders. (Atleast thirty.)
2.Get stone, or dirt, doesnt matter.
3. Build upward to a point where if you jump, you die.
4.Use the ladders to put along it so you can do it again.
5. Get the items you want to duplicate and climb all the way up!
6. Jump down, spawn, pick all your items up and walk atleast 50 blocks away.
7.Exit using the home button, double tap hope button and hold the Minecraft Icon till it shakes and press the exit on it.
8. Go to your Minecraft icon and click.
9. When you click, repeatedly press start so you immediately get pushed into your map. NOT TO MANY TIMES OR YOULL DIE!!
10.Walk to where you jumped and you will have all your items on the ground!! (When you first get back in, yes you will have your first items, when you go to where you jumped, thats where they will be duplicated.)
I have used this with my iPhone5 to duplicate Diamonds. If you have any issues let me know.