-Place an item in your belt, then take the item to be duplicated drop it on the ground. Walk away, then click on the item again. As you pick the item up, click the Left Mouse Button on an item in your belt right before taking the item on the ground. If timed correctly, the name of the item that was duplicated will appear in the box down below. It will have the same appearance as the item on the belt that was clicked on. Drop the item on the ground or place it in the back pack and it will re-appear correctly. However, don'tcreate a second item of the same type and put both on the ground. If this is done, the duplicate item will be destroyed.
-Drop the weapon to be duplicated, then walk about five paces away. Now open your inventory window and make sure you have a undesirable weapon or shield in the weapons window. Click on the weapon to be duplicated then click your weapon or shield. You will hold the duplicated weapon and the original will still be on the ground.
-Open a portal anywhere that has some space between it and the walls, then drop the item you wish to duplicate directly in front of the portal (in front, not under the portal) and close the inventory window. After that, step behind the portal. Once there, click on the item. If the item was placed correctly, your character should go in the portal's direction and enter it. When you show up in the town, open your inventory. You will see the item that was dropped is now placed somewhere in the inventory. When you get through the portal again, the item will still be there in the floor, but also in your inventory.