We do this every few months; When your dishwasher doesn't clean well, fix it yourself following these simple steps and avoid the expensive professional service call. A simple cleaning often solves the problem.
How to clean your cookie sheets--Kitchen Miracle Cleaner! You put about 1/4 cup of baking soda in a small glass bowl and squirt in hydrogen peroxide until it makes a nice paste. Then you rub it on the offending dirt/stain/grease...whatever! You can usually just use your fingers...but you can also use a small sponge at times as well.