A lot of cranks have been ruined by brake cleaner....it loosens the silicon in the crank. When the silicon desides to separate from the crank at some point you have a paperweight. The NovaRossi manual even says not use use it. They recommend "petrol"...which is gasoline. I use denatured alcohol in a spray bottle at the track and I have a gallon of diesel fuel at home for soaking my engine between races. Save an old toothbrush to clean the engine. I would "lap" that head button with some fine emery cloth on a piece of glass to eliminate hot spots. Check your shim stack with a piece of solder after to make sure you have enough clearance if you take a lot off the head while lapping it. Don't touch the piston though.
Just avoid the brake cleaner. The warning in the manual is there for a reason.