I had a model 28-1 like that once and I lightly used a very small amount of Flitz cream to even it out****b a small amount on a clean cloth-then rub a clean surface of metal other than the gun-when the cloth starts to turn light brown gently rub out the frame with minimal pressure-polish firmly with another clean cloth-one step should do it for you. Remember do not apply flitz directly on the gun or it can over polish or remove the bluing.