This is the third time I have shot my shotgun. (getting much better with the slugs and hit about 10 or 11 clays out of 15) I only had 15 birdshot shells. Anyway, this is the third time I have cleaned my gun and each time the mops leave stuff behind. It looks like little pieces of the fabric from the mops, but I am not sure if that is what it is. My first time I used the patches, but I ran like 15 or so patches through it and it still looked like crap so I started using the mops. I bought an extra 12 ga mop and use one with solvent and one with oil. I just can't get the barrel to look clean and smooth. Any tips?