From a purely metallurgical point of view this is a bad idea. Grinding metal tends to place tensile stresses in the skin during the operation from friction heating, and in the case of most aluminium alloys, the region at the point of contact is more than hot enough to start overaging.
Then, as the zone ground cools, it attempts to contract and reverse the stresses. However, the surface is weakened and the material below resists this compression, yielding the ground surface. Welcome to Crack City.
To try to remove material as gently as possible, and as gently as necessary is going to take weeks.