You normally have to defeat a Pokemon to get a key or you sometimes find it lying around on the floor.
Keys are found randomly around the floors of Solar Cave and Western Cave in Pokemon Mystery Dungeon.
There is no key, you must have a Pokemon with at least ten ribbons.
The key is laying on a table in the deepest part of the Pokemon mansion. You can find it lying on the table and it's used for opening the gym.
go on Pokemon Platinum Walkthrough you'll might get the idea.
The tanoby chambers are ruins where a certain Pokemon is lurking to find that Pokemon you must first solve the boulder puzzle in tanoby key once you do that you can find that Pokemon in the chambers.
You will need to work your way to the basement in the Pokemon Mansion, you will then find the Key.
You will find the key to the Gym of Cinnabar Island, From the Pokemon Mansion that is on the same island.
There is no key, you must have a Pokemon with at least ten ribbons.
The Special Key is a key item in Pokemon Diamond. You can find this item in a warehouse in Veilstone City.
In the house you jerk!
bgfhbfr
you find it in deep inside Pokemon mansion i think
You find a cave, go into it, then find a legendary pokemon, catch that pokemon, and then leave the cave.
you find the basement key in the underground path
u can find it in Pokemon mansion.
The key is laying on a table in the deepest part of the Pokemon mansion. You can find it lying on the table and it's used for opening the gym.
you find it in the galactic HQ
you can't.