I purchased a 9MM Shield last week and when I went to clean it, I noticed rust inside the barrel. I used what I had to try and clean it. This included Hoppe's No 9, CLP and Ballistol. I soaked and scrubbed with a bronze brush to no avail. I then used Scotch Bright patches run through the bore with a jag. After four or five run throughs, the barrel was free of rust.