Dispelling anger

When anger swells up and rears its head I wish to be rid of it quickly. For a moment of anger is said to burn a mountain of merit. In my personal practice I have gotten quite adapt at controlling my negative emotions and dealing with them appropriately. Patience is something I used to not know at all. Now I know patience well, and am able to keep my cool when things go sour. Lately though, even though I keep my cool, I can feel anger inside myself. It is not controlling my actions, but it is present, and I can feel it in my pulse, and in my body temperature when I breathe. I'd like to know if there are any practices related to this sort of anger. One that is not outwardly visible, but is present nonetheless.