Whether you run your dishwasher once a day or once a week, it's bound to happen at some point: A piece of plastic gets tossed around during the vigorous wash cycle, falls on top of the heating element and stays put there during the dry cycle. Now your dishwasher emits the peculiar smell of burning plastic and it's not exactly whetting your appetite for dinner. Spare yourself the hassle and expense of making a service call to an appliance technician. This is one dilemma you can easily solve yourself – as long as you have some baking soda on hand.
Ensure that your dishwasher has completed the wash and dry cycles. The knob should be turned to the "off" position before you open the door and get started, but give your dishwasher the proper amount of time to cool off before reaching inside.
Remove the object that is triggering the plastic odor. Chances are, a plastic storage container, container top or utensil is simply sitting on top of the heating element at the very bottom of the dishwasher basin. If the plastic object is stuck there, gently pry it loose with a wooden spoon. Check for any pieces of plastic residue and remove these with a paper towel.
Empty the dishwasher completely. Fill the soap compartment with baking soda. Set the dishwasher to a "normal" wash and let baking soda's odor-fighting capabilities flush away the odor.
Open the dishwasher door after the cycle is complete and, if the odor is still present, fill a small bowl with baking soda and place it at the bottom of the dishwasher. Close the door and let it sit overnight. To prevent any mishaps, tape a heads-up note to the dishwasher door before someone fills the dishwasher with dishes or runs the dishwasher with the bowl in place.