Do not use this method on silk, wool or dry clean only fabrics. Always test a spot first for color fastness. Hydrogen peroxide is bleach, it's safe, but it is bleach and could discolor the fabric.

Often using household bleach only causes stains to worsen. Hydrogen peroxide will not cause those problems. If you use a 3% peroxide found at grocery and drug stores it can be used full strength. Often a 50 -50 solution of peroxide to water works just as well. If you use a 20 to 30% solution then dilute with water 1 part peroxide to 5 to 6 parts water.

Pour the peroxide on the stain and allow to set 30 minutes. Then wash as normal using cool water. Air dry to make sure the stain has been completely removed. Heat sets a stain making it difficult to remove. If the stain is still present after 30 minutes use the peroxide full strength.

If the shirt has odors as well as stains, then fill a sink with cool water adding 2 cups of peroxide and one-half cup of baking soda. Wait 30 minutes and launder.