Heat of the Moment Anger:
--I close my eyes, take a deep, cleansing breath through my nose (a couple if I need to), and remove myself from the room quietly. Then I do a quick 'processing' of my anger alone in a bathroom, outside, in the car, etc. If I have to go back to the situation I make it clear it is not a good thing to discuss at the moment.
Slow burning and long lasting:
--Go away from EVERYONE for a few hours!!! Walk, talk to myself, get my ugly thoughts and feelings out and make a point to listen to 'happy' upbeat music that will put me in a better mood. I then process why I am so mad--hurt, betrayed, used, or injustice towards...--Is it going to matter to me next month, 6 months from now, next year? Can I deal with the issue or is it going to fester and continue to burn? Is the person and issue worth the hold over my life I am giving them by being mad? Would my life be better if the person/issue was removed from my life? How do I remedy the residual feelings?
*****One thing to remember, when you allow your anger at someone to linger, you have given them power and control over you and your feelings. It hurts you more in the long run to be angry, learn to be able to categorize the types of anger, put it into perspective in regards to your future and pick your battles wisely. Protect yourself from your temper, learn to ask "in the long term, does this REALLY matter--or is it just an irritation that is getting blown out of proportion?" Then figure out an effective way for you to diminish the anger--turn it into a productive learning experience and go on with your life. This is much easier said than done, but if you continue to strive for that balance it gets easier with practice.