Mine are all milspec so I don't have to clean them.
hahahahaha! "My used toilet paper still wipes so it must be fine".
To the OP, great topic but too little info. Here's a good article on what to clean and look at on your AR-15s, though we'd need a real gunsmith to post tolerance specs and fault measurements.
https://www.ammoland.com/2016/05/ar-15-maintenance-care/