We apologize for the inconvenience you experienced, Ange. The small holes on the iron base plate of the cookware expose the aluminum bottom of the pot to the air. As a result, the exposed aluminum can oxidize and become discolored over time, especially at high temperatures. However, we have a some helpful tip for cleaning the oxidized aluminum. Create a paste by mixing baking soda with water. Apply the paste to the oxidized aluminum surface and let it sit for a while. Then, using a damp cloth, gently wipe the surface before rinsing with clean water.

We are sorry to learn about your experience. We have some important tips for you to care the aluminum cookware set. 1) Always use on low to medium heat. 2) Always cool down to room temperature before washing. 3) Avoid sudden temperature change (thermal shock) on the cookwares and lids. 4) Avoid sharp adjectives touch on the cookware surface. 5) Should burnt grease or food residue collect on the surface, it can usually be removed with warm water and a mild detergent. For extreme cases, residue can be removed with a thorough cleaning using a Soft Scrub. Do not use abrasive cleaners, steel wool or coarse scouring pads. If you are still unhappy the set can be exchanged or returned anytime as part of the Member's Mark 100% Satisfaction Guarantee.