2014 Ford F-250 King Ranch 4X4
You can probably clean it with several bottles of brake clean, but that would take forever. I would either replace the EGR cooler or replace the guts. You can buy the improved guts for the 2015+ which flow better with a lesser chance of clogging immediately. Bullet Proof makes an improved core as well, but it will set you back about 1k. I haven't heard of many people going that route as there are cheaper routes one could take. Those cheaper routes may or may not offer mild weight reduction and an increase of spgs. You have plenty of options.