For the EGR valve I used brake cleaner (a little more benign than "carb" cleaner) with rags and brushes, worked fine. Do be careful with the electronics, just deal with the carbon; don't spray indiscriminately. Since I'm pulling the motor, I'll be going all the way back to the cat...
To clean the valve, wear an acid-resistant pair of gloves. Put on safety glasses, too, as the carbon deposits could become airborne in the process. Spray the EGR valve cleaner onto the carbon deposits. Remove the carbon buildup with the use of a pipe cleaning brush and dull scraper. Rep...