I have the magical ability to get nose bleeds spontaneously, and often enough that the school nurse saw me in the hallway of the school's office building today and knew exactly why I was there.
Anywho, it just happened during math class today and now I just stained my math notebook, great.
Fortunately, the blood didn't bleed through the other pages (It was a bit pricey for a notebook after all), but it's blood, and for obvious reasons, I would definitely prefer not to have it :)
Hydrogen peroxide gets blood out of almost anything. You can use a cotton ball for paper so it doesn't get all wet. If you get it on clothes just pour a little over the blood. It works if the blood has dried too. It doesn't work if you washed the fabric in hot water.
Just add a disclaimer like "blood stains, do not lick!" or something. It's something you throw away when it's full anyway and it will almost be exusivly used by you. Why care?
I would probably take a q-tip and dab at the blood with a tiny bit of hydrogen peroxide. It might bleach out any color, so only do that if the paper underneath is white. Really don't use much, and perhaps test first in some less important area of the notebook.
Blood probably isnt even in the top 5 worst bodily excretements that book has had on it that year. Literally nobody is going to care about teeny red spot on page 231. Dont worry about it.
This is more for fabrics than paper...
For blood stains, cold water is usually better than hot water.
Hydrogen peroxide or salt water might work.
Not sure that you can really remove a bad blood stain from paper.