I need to clean a head off a B18A. It has some dirt and sluge in it. I am not removing the valves. What is the best way to clean all that crap out??

Can you use soap and water then spray the entire thing down with WD40, or is this the stupidest idea ever.

 

take it to a machine shop, they will clean it...
I dont think i'd do the soap/water thing.

I got my head cleaned, and pressure tested for 30 bucks.