Posting to this very old thread, hoping to help someone else avoid a problem purchase. The pic posted by the OP is of an All Clad LTD pot that appears to have been run through the dishwasher, damaging the anodized exterior.
It's not dirty, it's damaged, partially stripped off. The coating on the exterior was not designed to be washed in a dish washer and has been partially removed. The choice here is to use steel wool, or similar to remove it entirely but it's not a great option. As there is aluminum under the coating, it will be a flat, dull finish. If shiny is the goal, then an All Clad model with a stainless exterior would be a better choice.
Here's a pic of what that pan should look like in good condition
All Clad LTD is my favorite cookware but even the later versions (LTD 2) purported to be suitable for the dishwasher, really are best hand washed. The Original LTD version of this pan will be ruined in the dishwasher and the manufacturers instructions make this clear.