Pull the lower rack forward and check the heating element at the bottom of the dishwasher. Remove any plastic items that are cool enough to touch. Let the heating element cool, and then scrape off any plastic using the edge of a plastic spatula or a scraper.
Pour 1 cup of baking soda into the large detergent cup of the dishwasher. Add dish detergent to the other cup, if you have dishes inside the dishwasher that have absorbed the burned plastic smell. Run the dishwasher through a normal wash cycle with the heated drying feature turned off.
Empty the dishwasher after the wash cycle completes. Pour 1 cup of lemon juice in the bottom of the dishwasher. Run the wash cycle a final time without any dishes in the dishwasher.