Good method: engine off. small hard plastic brush. open throttle valve. spray a little. scrub alot. Don't spray so much that it flows (this could flood the engine and damage a piston when it turns over). repeat 3-7 times. start the engine, spray-clean it heavily while engine running and throttle valve cycling (open&closing). cycle the throttle valve a few seconds & stop engine & repeat from beginning until satisfied.
Best method: Remove the upper-intake manifold, and spray and scrub it clean while off the vehicle. Alternateley, take it to a machine shop, and ask them to blast it.
