Stay away from Hydrogen Peroxide or cleaning products with "OXY" in them it's Peroxide in disguise.
I assume the blood has dried, so chip/flake off as much as possible, then vacuum the area,then mix 1 cup cold water,2 tablespoons ammonia,1 tablespoon or less mild detergent,apply solution to clean towel and aggitate the spots a little,don't scrub ! then blot with another towel or vacuum with wet dry vac, repeat until clean.