Laundry Detergent & Supplies | Costco- washing soap fabric washing powder washing soap ,Shop Costco.com's selection of laundry supplies to find a variety of laundry detergent, fabric softener, stain remover, odor defense & more.When To Use Bleach, Detergent, Fabric Softener, & Soap ...When washing cottons and linens only, use fabric conditioner (also called fabric softener) or dryer sheets to add scent, reduce static, decrease drying time, and ease ironing. While some detergents may have some conditioner in their formula, fabric conditioner is not the same as detergent.