The criterion for a large amount of blood and a small amount is custom

What is the amount of blood in which prayer remains valid if it is impure blood with a mitigated impurity?
As for what comes out of the two passages, it is impure, whether small or large, and it is not excused. As for what comes out from other than the two passages, such as what comes out of the nose, or the mouth, or a wound in the hand or foot, the general rule is that it is slight and does not harm, and its limit is custom,Meaning: what is customary as being slight.