Clean it thoroughly using "Kroil" brand penetrating oil and wipe off any excess. Get some Neco brand "Moly Slide" grease and put it on a rag and burnish it into the carrier outside diameter leaving a little dab on the sliding contact surfaces. By the time you've burnished in the Moly Slide, the marks pictured will probably be gone. Maybe even burnish a little Moly Slide in your trigger sear area as well. Go shoot 2000 rounds and repeat.
In my opinion, don't buy the high priced magic snake oil products, many of which can be corrosive. One key is if they claim their formula is so secret that they can't tell you what's in it, you can bet it is a load of bullshit. Kroil brand penetrating oil and a dab of Moly slide are all you will ever need to make an AR function as intended.