- Brush the excess stain off the surface of the fabric. Rinse in cool water to dilute the stain. Pretreat the stain with liquid laundry detergent, coating the stain without rubbing it in, and then let it sit for several minutes. Launder as normal. Make sure the stain is gone after washing, but before you place in the dryer or you may set the stain. Repeat if necessary.