Re: cleaning ar 15
First, There are a few things you might do so the bcg cleans easier. I like poslished parts and I hate any other gimmick finishes. Porosity breeds grime.
Degrease the parts.
Apply a dry lube.
Apply grease especially to the extractor pin, spring, rings, lugs, buffer spring, carrier rails and bolt tail. A mere film is adequate. Too much is when lube gets on the round below the carrier in the magazine.
Oil is for vaginas, and for guns when there's nothing else, or if grease use is a grave sin to you. Then use cheap, synthetic 90w gear oil. In a bind, any liquid is better than running an AR dry. Synthetic is always better.
Then, after firing the AR, everytime, clean it. Stubborn carbon will not accumulate when the gun is treated right.\
Good shooting.