You can't. You can re-arrange them so that the ones you want are at the top using select, though.
Chat with our AI personalities
you can't delet key items in any Pokemon games.
The Secret Key that you get in the Pokemon Mansion is used to enter the Cinnabar Gym.
You will find the key to the Gym of Cinnabar Island, From the Pokemon Mansion that is on the same island.
You have to find the key in the abandoned mansion.
On the 5th floor of silph co.