How to duplicate items:
Put an item with a x symbol in the sixth position on the item list.
Go to the man in Viridian City and ask him how to catch a Pokemon.Then fly to Fushcia City and go south until you reach the water.
Walk to the wall on the left and face the water.Surf and follow the wall until you reach the shore of Seafoam island.
Dont go on land but surf up and down on the coastline.Soon you will find a pokemon called Missingno.Dont catch it or fight it.
Run away from missingno. and the sixth item on the item list will be duplicated.
Added by: The Cheat Master.. , ID#1489