My method is to totally de-grease, then mask up all passage ways holes and gasket surface with good quality gaffa tape , blast the items be it head barrells crankcases, airgun all loose blast media, and jet wash , then heat dry in oven and and blast with air again, if any trace of the blast media is left i repeat the jetwash heat dry and air blast process
bung up any thread holes, and mask up all oilways ,