Originally Posted by
DrIsotope
Depending on how deep the coloring is in the anno, you can often bake the color out. I've done it many, many times with aluminum parts of all colors. Try baking the chainring at a high temp (~450º) in a toaster oven for an hour or so. If the anno isn't deep, it will go to clear, if it is, it will end a sort of titanium/gunmetal color. If it ends the titanium color, you can always strip it afterward to get to the bare aluminum. Just know that the bare aluminum surface begins to oxidize immediately, so unless you like dull gray, the polishing process is never ending.
And what does that do to the properties of the aluminum?
Aluminum Workshop: Achieving T6 designation for 6061 - TheFabricator.com
"....So we have a solid solution of magnesium, silicon, and other elements in aluminum at room temperature. This is called the T4 temper. If we take this material and heat treat it at a temperature between 325 and 400 degrees F, the alloying elements begin to form ordered arrays of atoms in the aluminum matrix. These arrays are called GP zones, and they strengthen the aluminum considerably. This heat treatment is called aging, which results in material with a T6 temper...."