i found this online for it, i know anodized metals cant be removed like paint becsue its a TOTALLY differant process that makes metal takes on the color.
"There are 2 way to accomplish the removal of the anodic coating from aluminum depending on the surface you want to end up with. A NaOH etch solution will remove the coating but will etch the surface leaving a diffuse (matte) appearance. The chromic acid/phosphoric acid solution used in the Acid Dissolution Test ASTM - 137 will remove the anodic coating without affecting the underlying surface. The composition of that bath is 80 grams of chromic acid in 3.5 liters of water, add 140 ml of 85% phosphoric acid, add water to make 4 liters. The bath is operated at 190 - 200 deg. F. Immerse the part for 15 minutes and then rinse well in water."
i also read that over cleaner may do it. Anodizing is no joke. do you plan to re ano it?