Most of the dish washer detergent companies address the issue on their help website. The best solution is to always hand wash aluminum cooking utensils and other aluminum items. We have answered the question in this forum and one of the answers is copied below.

Dishwashing soap companies are now eliminating phosphates as required by new legislation in many states. According to Cascade, one of the benefits of phosphates in dishwashing was its ability to help protect the surface of metals. With the removal of phosphates, discoloration on aluminum may now occur faster than before. Make sure that you always check the product labels and/or manufacturer of your pots and pans to make sure they are dishwasher safe before you clean them in your dishwasher.

Most aluminum is best washed by hand to eliminate the change in color and feel. If you are having problems getting the rest of your dishes clean you can try the following suggestions. For light soil, adding one-half to 1 teaspoon of baking soda to the detergent holding area. Also add 1 teaspoon of white vinegar to the liquid spot removal compartment and run through the cycle. Another option for heavy jobs is to put 1 tablespoon of baking soda plus 1 tablespoon of borax into the reservoir. The dishwasher will do the mixing. Also add distilled white vinegar to the rinse dispenser. To use the dry mixture for future loads, mix up a container to keep on hand near the dishwasher and add 2 tablespoons of the mixture to each load. The good news is the pans are still ok to use. If you have any additional questions feel free to contact us again. <personal data hidden> www.extension.iastate.edu/answerline

When washed in a dishwasher, aluminum cookware can react and darken due to mineral content in the water, chemicals in the detergent or high heat from the dryer. Natural products such as lemon juice, vinegar or cream of tartar remove discoloration and provide fast, effective results without damaging the metal.