What is the difference between a Mill and Anodized Finish?

Anodizing is an electro-chemical process used to promote the growth of aluminum oxide, which is then color dyed and sealed. This process gives the aluminum a decorative appealing finish, which also significantly reduces the corrosion of aluminum alloy. Non-anodized aluminum, also known as “Mill” finish, when exposed to room temperature (oxygen) will begin the natural corrosion process, which produces an aluminum oxide on the surface. Mill finish is more susceptible to scratches.