LPT: If you got blood on your clothing, simply soak it in cold water and it will come off

Probably a well-known tip but a tip that I didn’t know about until I cut my arm and got my own blood all over my white shirt. A paramedic told me to soak in cold water, which I did and it came right off

EDIT: THANKS to everyone saying that hydrogen peroxide works better. However I doubt that every person has hydrogen peroxide laying around :’)