i am a part time, hobby gun dealer. i specialize in antique and collectible firearms. i particularly like sxs shotguns. i use the services of a professional gunsmith. he has been working on guns as a full time profession since 1946. he has thousands of satisfied customers. many of those customers have had shotgun receiver case color enhancement work performed by this gentleman. he uses a low controlled heat and chemical process to cosmetically enhance shotgun receivers. over the years, i have had about 25 shotgun receivers case color enhanced via his method. most have been sold rather quickly. i have yet to have a return or a complaint. one cannot stay in business over 65 years and not be getting it right most of the time.