I don't know if this is a problem or not, but how do you get the gunk that gets caught on the crown of an AR when it has the standard A-2 flash hider? It seems the inner diameter of the flash-hider is slightly larger than that of the bore. So there's a tiny platform for gunk to sit on the crown. I can shine a flashlight on there and see it all pooled in there, but not even a q-tip is small enough to scrape it off because it sits right in the corner. Any suggestions?