Note: you must have 2 characters on different iPhone/iTouch.
Also make sure Bluetooth is enabled on both devices. (Will not work with the "Local Wireless" game connectivity).
In these instructions, I have designated one iPhone to be "iPhone 1" and the other "iPhone 2," to distinguish between the 2 characters during these instructions.
1. On iPhone 1, select a character with many items: weapons/armor/rings. (I recommended a high-level, strong character with no need for the items.)
2. Tap "Start Game"
3. Tap "Multiplayer"
4. Tap "Bluetooth(R)"
5. Tap "Host Game"
6. On iPhone 2, select a character with little or no items or money.
7. Tap "Start Game"
8. Tap "Multiplayer"
9. Tap "Bluetooth(R)"
10. Tap "Join Game"
11. On iPhone 1, Tap "Start Game."
12. During the game, manuever both characters to one of these areas where the glitch is possible:
a. At the "Bogwomper Camp," when you break from your cage with Rene and Celeste and get to the camp where you can sell/buy stuff at the vendor.
b. In the "Lighthouse" area, this glitch is possible when you finish a level of almost every story in the Lighthouse. When you go through a self-activated portal, stay at the very beginning of the next story.
c. In "Alastor's Domain." When you go over the really long "rainbow arch," and there is a chest to the right, the area directly below that chest.
13. When you arrive to any of these locations, open the inventory on iPhone 1.
14. Drop AT LEAST 10 of your un-needed weapons/armor/rings. (EXIT YOUR INVENTORY AFTER YOU'VE DROPPED THE ITEMS)
15. On iPhone 2, move your character only a few inches to pick up all the items.
16. On iPhone 1, you should be able to pick up all the items that you dropped.
17. Now both of your characters have every item. Either character can sell them to gain money fast, or can use them to become stronger. (Note: the items duplicated still follow the "rules of equipping." You must have the required strength, dexterity, or energy to equip.)