Here's the corrected link in bruce m's initial posting.
https://connecticutshotgun.co/case-colo ... ement-kit/
Here's some info on the subject from my book on the Browning's.
Wayne
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I discussed case colors and case hardening with Tom Ivanoff who developed the process used by Miroku. In his opinion the case colors created by using potassium cyanide are more durable than those created by the bone and charcoal process. But regardless of the process used to create them, case colors are sensitive to UV radiation and will eventually fade if exposed to sunlight for extended periods of time.
Harsh chemicals such as solvents and high viscosity penetrating oils can accelerate the process and may result in the complete loss of the colors in periods as short as a few weeks. Some gun owners have used various coatings such as varnish, lacquers, or even fingernail polish to protect the finish. Museums and collectors of high quality firearms have known for some time that the best method to protect metal surfaces, including case colors, is to coat the surface with a good quality non-acidic micro-crystalline wax and store the firearm in a dark and controlled environment. Renaissance Micro-Crystalline Wax Polish is the preferred brand used by museum curators. It’s available from MidwayUSA and Brownells. Since Renaissance Wax is relatively expensive and is not likely to be locally available, a couple of frugal alternatives are Butcher's Bowling Alley Wax and SC Johnson Paste Wax for floors. Butcher’s Bowling Alley Wax is the preferred alternative. It’s a clear paste wax, blended of carnauba and other fine waxes in turpentine and mineral spirits. Samuel Curtis Johnson’s paste wax has been around for close to 120 years and still does a good job protecting wood, leather, plastics and metal. Although I have not tried it, another suggested option is to use Lemon Pledge. But bear in mind that Lemon Pledge contains silicones. It may work fine for protecting metal and wood surfaces but if it soaks in the wood, refinishing or touching up the stock or forearm will likely result in “fish eyes” or small circular imperfections in the surface.
Another technique to protect the case colors is to apply a hard coating such as Brownells’ Metal-Coat Epoxy, a clear, tough, epoxy paint used to protect polished or bead-blasted steel, aluminum or brass surfaces. It’s available in an aerosol can. Brownells advertises that one coat provides superb rust resistance, plus additional coats bond into the base coat for more scratch protection. It’s reported to hold up well to gun oils and solvents although some of today’s more aggressive, “super” bore cleaners may damage it. The soft luster looks great and maintains the beauty of color case hardened steel.
I enjoy shooting and handling my firearms. Therefore, the action will be exposed to ultraviolet rays, body oils, cleaning solvents and oil solutions. I’ll “pick up” a can of Renaissance Wax or Metal-Coat Epoxy one of these days, but until then the case-colored metals on my guns are coated with SC Johnson Paste Wax and stored in a well-controlled environment in a large gun safe. If you handle, shoot, and routinely clean your firearms, there’s no getting around it, the case colors will fade to some extent. The best you can hope for is to substantially slow down the process.