A Maytag Neptune washer may develop odor from excessive use of laundry detergent, leaving the clothes in the washer too long, or standing water in the seal. Keeping the washer closed for long periods can also lead to odor.
Give the washer a thorough cleaning by mixing 1 cup chlorine bleach with 2 cups warm water. Use the mixture and a rag to wipe down the interior drum of the washer, as well as the rubber seal around the door. Pour chlorine bleach into the bleach dispenser and run a complete hot water cycle without any laundry.
Leave the door to the washer opened when not in use to allow air to circulate throughout the machine. Only use high-efficiency detergent and do not use more than the recommended amount. Remove clothes from the washer as soon as the cycle is complete and run a clean cycle about once a month with just bleach and hot water.