I was curious if it was ok do do it this way because BMW told me that the cylinder head had to come off to do it. I'm going to try blasting the swirl flaps since I took them out and have a delete kit. If they get damaged by the baking soda then I wont use it on the plastic part on the valve cover area. I looked at it with a borescope but I cant see any bare plastic so how far down does the plastic go?

Sorry if I'm asking dumb questions, I just want to get this done right.