Duplication Glitch Minecraft Bukkit R4.0

step1: You will need a freecam that when you break a furnace it keeps the gui screen open. Also an insta break.

step2: Start smelting (in this example I will say iron) then when you have 1 iron ingot cooked break the furnace in freecam with insta break (I like to use wooden pickaxe) then open it before it actually gets destroyed.

step3: The iron you smelted will become an infinite block but if you take it you will get kicked for internal server error. So you will need to really really really quickly stack it onto another iron ingot before you get kicked.