1. Open the Pokemon game on your Nintendo DS or 3DS console.
2. Go to the main menu and select "Bag".
3. Go to the "Key Items" section of your bag.
4. Find the Archeus event item and select it.
5. Press the "A" button to view the item's information.
6. Press the "X" button to delete the item.
The Archeus event item will now be removed from your Pokemon game.
Note: Using an action replay or other cheating device to obtain items in your Pokemon game can have negative consequences, such as corrupting your save data or preventing you from accessing certain features of the game. It is not recommended to use cheating devices on your Pokemon games.