How to clean the egr valve
 

I have a CEL and pulled code for egr valve not working right. I put on a salvage yard sensor and no change. I pulled off the two bolts holding on the top of motor and cleaned up some. Not really dirty. I guess I am asking it I loosen the bolt holding on the egr tube it this is where it will be gumed up and needs to be cleaned. This bolt is really rusty on my truck. What size is this bolt. I don't have the right size wrench for it. I can not buy a new $200 erg valve just now. Thanks for any help guys. This is on a 92 f150 6 cyl 300 ci 4x4 short bed 5-speed regular cab stock two door xl rusty green bench seat roll up windows no air 31" tires 152,000 miles LOL 3.08 gears too!

I just used some brake clean and parts cleaner on my. I have a 5.0 and don't come across any of the old inlines at work so I don't know the size of the nut.

Before you put it back on try to blow through it, (you should not be able to). Then try to bloe through it while you have it hooked to a vacuum pump, it should open. If not then it is either still plugged or it is bad.
What exactly did the code say? insuficient flow? Too much Flow?

From my experience, usually when that needs to be done its better to just buy a new one. Cleaning it may or may not help. If it does, its likely that the problem will come back later. I would check to make sure that the sensor on the EGR is not the problem.

It's easily removed for cleaning
I sprayed it top and bottom with WD-40 and soaked it
then with a racket wrench extension i gently actuated the valve in and out a few times
blew out any particles with air duster, and repeated that about 3 times, the reinstall being careful the gasket didnt disintegrate(which is likely will, these are cheap)
I havnt gotten a CEL since so i think it worked