I found a little trick that I will share with you,I have owned several Remington 1100's and the hardest place to clean is the gas ports, as a toolmaker I had access to catalogs of a large variety, while looking through one I discovered miniture bottle brushes ( I used the tern bottle brushes as most people with kids know what they are) in two sizes and I thought why not I ordered a package of 6 in each size they worked great and when I bought a over and under with ported barrels same results.

If I can find the manufacturer again I will post it later, they are bristle not brass or copper.

pipe cleaners also work well, the kind with the hard plastic brustles in them made for cleaning pipes, not the craft type