If you have an aluminum part that has had some repairs and now shiny spots, you can tone down the repair area to match the aged surrounding aluminum with Clorox Bleach. It works best also in the sun. The heat accelerates the oxidation, but the sun will tend to try out, so repeated applications with a brush will dull those shiny spots to a nice aluminum gray. I have also let sit over night to wake to a lot of whited oxidized aluminum easily brushed off. Patients is the key to get to the right level of aging. Rinse well with clean water when done.
If you have a freshly media blasted aluminum part, a spray bottle with Clorox Bleach might be in order to cover the entire part to tone down. Be sure not to perform on your wife's favorite table cloth. You will get in trouble. Do it outside.
Best of luck
Cory