3
I don't have great photos of this, but I think you can get the idea.
I basically took one of the cheap, shitty siphon feed sand blast guns, removed the pickup tube, replaced it with a hose, dropped that in my parts washer, turned the pressure down to 40 psi, and it cleaned the ever loving crap out of my head and valves with very little effort on my part.
I'd recommend caution when aerosolizing flammable liquids in your shop also, but it worked tits for me.