soapy water for a minimum of half an hour before scrubbing away the grime. This works, but requires a lot of sink space. Baking soda and boiling water can also do the trick, Oven Pride suggests ...
The baking soda will remove stains and freshen the dishwasher ... A basic mixture of dish soap, water, and white vinegar makes a great homemade cleaner that’s safe for all dishwasher surfaces.