Summarize the following:
Do not use warm water. For older insect stains you have to soak it longer. If the stain is still visible, repeat the soaking process.
Scrape off the excess crusted matter using a brush. Mix 1/2 teaspoon liquid detergent with enzymes, 1 tablespoon ammonia and 1 quart cold water in a basin. Soak the fabric for at least 30 minutes. Wash the fabric as you normally would.