This is a glitch on Dead Island which will allow you to duplicate weapons and items. It is very easy and can be repeated as many times as desired. This glitch is unpatched so there is no need to clear your system cache.

1) Play in solo mode and stop when you pass a checkpoint
2) Crop the weapons or items you want to duplicate on the ground.
3) Then, kill yourself by using Deo-Bombs or Molotov's.
4) As you die and the screen goes red, quickly pause the game a reload your checkpoint.
5) When you respawn, the weapons and items you dropped will still be on the ground and also in your inventory.
6) Simply pick them up and you will have two of everything you dropped.

Note: You will not lose the money lost from dying as you reload the checkpoint and don't actually die.

If you are having any problems, watch this video: