Soak immediately in cold, salty water. Don’t use hot water as it will set the stain. For heavily stained items, keep changing the water until it is clear, then wash with laundry detergent, such as Persil Advance. If the stain is old or persistent, soak in cold salty water for several hours and then wash as usual. For very persistent stains soak in a tepid solution of Persil Advance. Rub gently around the edge of the stain with the soaking solution before leaving to soak.