worth cleaning intake plenum?

I'm doing the driver side valve cover gasket. The upper and middle intake plenums are carbon caked. Is it worth trying to clean them with throttle body & air intake cleaner? I'll try to find a round long-handled flexible brush locally in the morning (holes are 1.5"), but that's going to be tough, and without one I'm concerned I'll just be loosening the carbon and cause it to flush into the engine. The lower plenum, which I'm leaving on the engine because the valve cover is accessible now, looks the same as these, and I don't know how much good cleaning these alone would do.

 

No

 

plenum Probably not but,
What do the actual valves look like?
From the top looking down into

 

Inside the valve cover right? I haven't opened that up yet. Have to resume in the morning. Here's my best pic of what the passenger side looked like.

 

No, under the blue tape on this photo you will see the valves.
I run methanol on my supercharger so mine are extra clean

 

For what it's worth, when I did my valve cover gaskets, I used a foaming engine degreaser and a small brush and just went to town on the upper and lower intake manifolds. Mine were not as caked as yours though. It's probably not hurting anything to leave them dirty, but they weren't hard to clean.

 

Ok, I learned something new! All of them look like this one. A mess all the way in, but fairly clean valves?

 

I'd call that fairly normal. You really cant clean them with any chemical and you risk deposits falling in. I'd just leave that personally.

 

They look fine, a little bit of build up but I would not worry about it.

 

I have the 4 banger.....but did same thing....
left lower intake on......and cleaned the heck out of the upper...
thats where the vac passages, egr passage and its sensor all get carboned out....

Couple cans of oven cleaner.....giant bottle brush.....

 

marvel mystery oil will completely dissolve carbon too if you let it sit on the carbon overnight, FYI

 

No, the carbon/oil gunk is actually filling the porosity making your plenum smoother for air anyway. Valves are clean.