Duplicated items in game

It has come to our attention that someone has worked out a way of duplicating or creating items in RuneScape unfairly. Particularly it seems they are doing this with christmas-crackers which produce party hats.

Obviously this is a pretty obscure problem, since it's taken over 10,000 combined years of RuneScape playing for anyone to find it, but we're determined to close this hole.

Update: This problem is now fixed, thanks for everyone who offered help. With respect to the reward we offered, this will be given to the person who sent the first email explaining how the object creation was done.