When I purchased the CT the carfax reported a history of the head gasket being done 18k mile ago. Although a head gasket was done, there was no history of the EGR valve, cooler or intake being changed out or cleaned. Being serviced at Lexus I was pretty sure no cleaning of these said parts would occur so as preventative maintenance wanted to address all the GR components including the intake manifold.
I am not not a huge fan of rushing things and knowing how picky I am I chose to just get a used EGR valve, cooler, piping and intake manifold etc. Obviously buying used with current prices online and then working on it seemed non beneficial to me and so was planning on just buying new EGR cooler and clean the valve, and intake manifold when I took it out. I had gone to the local pick your parts but all the Priuses already had the engine removed. Last week they had one listed and the listing was only 2 days old. Rushed to the junk yard after work and luckily everything was still there. Pulled off the EGR valve, cooler, piping, intake manifold, injectors etc.
There are a bunch of how-tos on removal, cleaning and installation of said components so I don't feel like I need to reiterate it here. Also thank you to the everyone that do videos and guides etc. to make things easier for us. Some things I did do differently though so just wanted to point some things out.
I left the valve connected tot he cooler and blocked off all the open ports and filled it with carburetor cleaner. You can use aluminum tape for this, vinyl tape and paper will not work. I let it soak for a day or so and then started cleaning.
The intake manifold, cooler, piping, valves etc. were all nasty and definitely clogged up. This was what came out of the initial rinse from just the intake manifold.
With the brush bits I cleaned up all the piping etc.
For the EGR cooler, leaving it soaked in carberator cleaner I think definitely helped. Used a thin welding road and noticed that it would go through fairly easily from one end to the other so then I used a pressure washer to clean it out. With light coming through from the other side I was very happy with how this turned out.
As for the EGR valve I ended up disassembling it to clean it out.