Unfortunately, due to the direct impingement gas system ALL ARs get dirty. The old adage being “They ISH where they EAT!” I’ve never found it a problem. Run ‘em wet and you won’t have a problem. When I was an instructor, the majority of ARs that had a problem with jams was due to being dry. First thing I would check on student’s rifle! Then I’d tell them, “lube it up! AR likes running wet!”