Wash cotton sheets in hot water, preferably above 120 degrees Fahrenheit. Hot water washes kill bacteria, including those that cause odor. Wash sheets made of synthetic fibers in warm water between 85 degrees and 105 degrees Fahrenheit.
Use either powdered or liquid laundry detergent in every wash load of sheets. A heavy duty detergent or one that contains odor-reducing enzymes works well for badly soiled sheets. Use the amount indicated on the label for the size of your wash load.
Remove the sheets from the washing machine promptly after the wash cycle ends. Leaving wet sheets in the washer can lead to mildew growth or a sour smell in the sheets.
Add a fabric softener sheet to the dryer when drying bed linens. Fabric softeners help soften the sheets, and they contain a fragrance that helps mask or reduce any remaining odors in the sheets.