What is a good way to get blood stains out of someone else's clothes?

I have tried club soda, and other stuff! but the stains will not come out! its been a while since it happened. but the stains are still there! and i need to get rid of the blood stains quickly. or else i will be in serious trouble! and i still need some sulfuric acid and a bathtub! i wish my friend did not sc his knee and force me to clean it so close to our science project deadline!