Well......, this is kinda hard but, i dont play leafgreen or fire red now. but, i help you with something. when you,re in cinnabar island. you go in the mansion and walk through a lot of stairs. if you have trouble with attacking pokemon, use repel or super repel. i hope that help.
In the house you jerk!
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 have to find the key to the Cinnabar Gym there.
u can find it in Pokemon mansion.
You will find the key to the Gym of Cinnabar Island, From the Pokemon Mansion that is on the same island.
you find it in deep inside Pokemon mansion i think
you find it in the Pokemon mansion
Find the key in the pokemon mansion on the same island.
You have to find the key in the abandoned mansion.
You will find it in the Pokemon mansion on cinnabar island.
the key is in the basement of the pokemon mansion
You can find the key to unlock the door in Pokemon mansion