Use vinegar to clean and de-clog
If gunk and goo buildup in your dishwasher—caused by food deposits and hard water—is minor, you can often remedy the situation by running a vinegar cycle. Simply pour three cups of white vinegar in the bottom of the empty dishwasher and select the longest cycle.
The vinegar will dissolve light mineral buildup and clean gunk from the holes in the spray arm. It will also remove residual grease from the interior walls so dishes will be cleaner and smell better.