Camphor is extremely purgative it is also EXTREMELY strong, so use it judiciously. When burning camphor, it has a heavy menthol smell that can be difficult to breathe in, so again, just use a little at a time and add more as needed. For this reason, while it can be used for indoors, I burn it for outdoors only.
Camphor can also be used to seal a room against spirit presences by first cleansing a room, and then placing chunks of camphor resin in each of the room's corners. If you cannot seal a room in this manner - for instance if you are not staying at your own home - you can place a piece of camphor in a glass of water and keep it under or beside your bed for spiritual protection.
Again, use it judiciously but when you do need to use it the Camphor is Very Effective!