In all the years I and my fellow soldiers cleaned and maintained our rifles about the only "supervision" we got from the armorers was when attempting to turn it in was for the armorer to stick a q-tip somewhere and find a bit of grey on the swab and say "No, it's not clean." Regardless weapons aren't supposed to be sterilized and the standards were/are "oiled, clean and serviceable." More weapons have been worn out from over cleaning than expended in combat IMO.