Asked in Car Shaking Problems
What type of cleaning solvent do you use to clean the engine head?
Most shops use something called "Stoddard solvent", which is closely related to dry-cleaning solvent. Stoddard solvent is used to clean most oily parts. It's also good to have a stiff brush that can be used to break loose the stubborn stuff.
If you're talking about cleaning the head while it's still in the engine... most of those are just away to separate you from your money and don't really work.