i have a cylinder block that is greasey, oily, scaley and generally manky. how do i go about cleaning it up?

honing tool for the chamber walls. some flat facing here n there. but what about the rest?

in particular im concerned about the oil and water ways. the water channels have that brown deposit you get when you use tap water.

i cant simply take it to a specialist place either cos i live on an island off the coast of scotland.

would ultra sonic cleaning do much use?

any help much apreciated.