* Soak / Scrub * cycle of the dishwasher.
Pressure wash first. Put in the dishwasher using the toughest setting. Make sure the Jet-Dry is full for no spotting .....
Once done, run it again empty.
All of this is of course, to be done, when the wife is out of the house for a few hours. It really does work good, I do it all the time with my aluminum W-31 Olds intake. Soon, the intake off of the Biscayne is gonna get "the treatment" ......
Disclaimer: I am by NO means responsible for any domestic disputes which result directly or indirectly from the use of the household dishwasher to clean parts.