Crash when exiting application.

I'm using a statemanager and multiple scenemanagers for the different states.
Each state loads the geometry, lights, vehicle, world and so on.
When exiting from a state with the prefab vehicle and ogreode world, it crashes.
At work right now so i dont have the code but could you tell me the proper way to destroy everything ogreode and unload it?

Does delete mVehicle and delete mWorld do it or should i call something else manualy?

Does delete mVehicle and delete mWorld do it or should i call something else manualy?
That should be ok.

Need more info on the crash or a way to reproduce it.

You probably know this already but make sure you always delete mWorld after mVehicle.