I have a blued trigger housing, from a 1100 Remington, that I want to remove the blueing from. The housing is aluminum. What's the best method for removing the blueing without causing damage to the aluminum casting.
If it is aluminum, it is not blued, not possible, as bluing in and of itself is a controlled rust (rust being iron oxide), and since alum contains no iron, hence no bluing.
Depending on the age, if it is in fact aluminum, it is either anodized, or if it was made in the last couple years, it'll be powder coated.
Either way, the only way to remove it will probably be abrasively. At which point, you'll have a bare aluminum piece, which after time, will loose its polish/luster as it builds a layer of tough aluminum oxide, unless you put some sort of protective sealant on it (it can also be clear anodized).
One day, I had the miss fortune of leaving a Remington really dirty looking like baked on oven crud, aluminum trigger gaurd in the hot soapy water to long, it came out white. This hot soapy water is **** an span detergent working just below a boil.
if you know someone with a hot tank the, hot caustic will remove the coating, it should foam gently, this is how the plating shops get the anodizing of aluminum, if it fizzis violently remove right away as the solution is to strong and will cause damage. Also never let it out of your hand when doing this, rinse and check often. If you have all the steel parts out of the guard, a quick dip in Nitric acid will high light any anodizing that hasn't been removed.