Soak and agitate a fresh stain in cold water before washing. If hot water is used first, it cooks the protein, causing coagulation between the fibers in the yarns of the fabric, making the stains more difficult to remove. If the stain is dried or old, scrape or brush off any crusted matter, then soak in cold water using a detergent. 

After treating the stain, launder in warm (not hot) water, rinse, and inspect. If stain remains, soak an additional half-hour, then rewash.