Better to use chemicals to remove the anodizing. You must get ALL anodizing off or the finished trim will look terrible. On all the tight spots it will be hard to get it all off, you will sand too much on the corners and alter the shape, and make thin spots. If you don't believe me, try it on a junk piece first.

Oven cleaner will remove it. Immersing it and soaking it off is bad, you want to leave the anodizing on the backside of the trim, it can corrode and get holes eaten in it where it retains water. Also the anodizing adds strength and rigidity to the aluminum trim.

So use chemicals to remove it on the visible sides only, clearcoat with automotive quality clearcoat it to keep it from going dull.