Mine eyes are made the fools o' th' other senses, or else worth all the rest. I see thee still, and on thy blade and dudgeon gouts of blood, which was not so before. There’s no such thing. It is the bloody business which informs thus to mine eyes. (2.1.45-49)
Will all great Neptune's ocean wash this blood clean from my hand? No; this my hand will rather the multitudinous seas incarnadine, making the green one red. (2.2.63-66)
Here's the smell of blood still; all the perfumes of Arabia will not sweeten this little hand. O, O, O! (5.1.44-45)
Blood is often synergized in Macbeth with appearance versus reality. In act two, Macbeth hallucinates prior to his murder plans, and sees a floating dagger with blood on it. The blood on the dagger represents King Duncan's blood that is going to be shed according to Macbeth's murder plan.
Again, blood is used to symbolize the evil doings in the play. Macbeth can't change what has already been done in the past. In act two, scene two, Macbeth is trying to wash his hands clean with water to forget about killing Duncan, but his hands are stained with supernatural blood that can't be washed off.
Blood imagery is used in act five, scene one, when Lady Macbeth is sleepwalking, trying to wash away the supernatural blood on her hands that represents her evil doings in the play. Similar to her husband Macbeth, Lady Macbeth can't wash away the blood because it's not real on Earth. The blood is her guilt and evil actions from her past.