Hydrogen Peroxide is great on organic stains like blood. Mayo is a grease stain. For grease I use what mechanics use to get grease off their hands and clothes. A tub of hand cleaner you can find at auto stores. You can try Ritz or Carbona color remover, then redye the shirt if the spots don't come out. Hint: When I find a clothes basic I like and wear a lot, I buy two of them. Sometimes more if it has to be washed a lot.