Item Duping is a glitch that allows you to duplicate almost any dropable item in Godzhell or any other RSPS. Players may call it dupe, duplicating, multiplying, item duping, or item duplicateing, they all are the same thing. The Duplication Glitch was the most famous glitch of the Runescape classic. It was exploited on 7 November 2003..
There are several methods and different ways of duplicating your items. You may get banned for using following methods. These are: logging in with same account in multiple browsers or computers, doing a duplication with trade function or using some third party program to manipulate with your account. You can find and learn about different methods from youtube.