with regards to engine cleanliness i remove everything that is not part of the casting, chase all threads, deburr any flashing/sharp edges as required. use a high pressure washer and galley brush set along with dish detergent for final wash. it's especially important to use the high pressure washer with a 0° tip for cleaning the water jackets if you're going to grout the block. you can also use acid though i've never personally done this. this is AFTER it has been hot tanked. i spend a LOT of time cleaning parts and when doing a block wear a raincoat and face shield because i really have at it with the pressure washer. there's always the potential for casting sand to be stuck in many places. i have tons of brushes of all sizes and lengths and also have two separate cleaning tanks both of which have filters on them.

my father made it simple to understand when he told me "you can't get an engine too clean"