Is it possible to clean a turbo without removing it from the engine and if so can anyone suggest what the best fluid to use. Thanks.

 

What makes you think you need to clean the turbo?

As it spins at very very high rpm's, the vanes do not really get dirty as centrifugal force will not allow anything to adhere to them. Usually, the bearing gets coked. Then you need to rebuild it or have it rebuilt.