its to the left of the pokemon gym on cinnibar island
Go into Pokemon mansion which is found on cinnibar island once inside wait until a wild Pokemon appears. Grimer is not that rare to find but you can find it.
Cinnibar Island
Cinnibar island if your going in order.
The Celadon Mansion is the large building by the Department Store and Pokemon Center.
No you find it in Pokemon mansion.
Either train a Koffing or catch one in Pokemon mansion which is located on Cinnibar Island.
on Cinnabar Island.Pokemon mansion is on cinnabar island if you don't know how to get there go to pallet town then go south surfing on one of your Pokemon and there your at cinnabar island.
On cinnibar island.
Go into Pokemon mansion which is found on cinnibar island once inside wait until a wild Pokemon appears. Grimer is not that rare to find but you can find it.
Explore the ruined mansion to find the key.
This badge is given to you by the Cinnibar Island gym leader you can\'t enter his gym until you have the Secret Key which is hidden in the basement of Pokemon Mansion which happens to be on Cinnibar Island.
Cinnibar Island
In the cinnibar island gym.
Cinnibar Island Hope this helps
on cinnibar island it is the top left building
South of Pallet town.
In the cinnibar island gym.