Soak in warm water or cold water. An enzyme soak product may help. Brush area vigorously with a paste of detergent and hot water.
Soak immediately in cold water, then sponge with a borax or vinegar solution.
Rinse area with cold water immediately. Rub in a couple of drops of a mild, white dishwashing liquid and rinse well. Then treat with a mixture of one-part white household vinegar and three-parts water. Rinse again and launder as you normally do.