You cannot let go of anger, only wisdom can let go of anger. Only wisdom can prevent defilements from arising.
Awareness sometimes cannot. Awareness knows the object – craving or aversion. Then you watch, watch, watch and learn something. When understanding comes, then the defilement disappears.
Sometimes when you watch for a long time, defilement cannot grow because you cannot think, then slowly the defilement fades away. When you’re aware continuously, the defilement doesn’t have a chance to think about the storyline. The defilement calms down.
There are two ways that the defilement goes away: one is because of concentration – if you are aware continuously, the mind cannot think about the story; that’s why defilement has no chance to come.
Why does defilement continue? Sometimes defilement arises and continues a long time – the whole day, the whole evening and even into the next day – because you allow the mind to continue to think about the story – you feed the defilement; you’re thinking about the storyline again and again.
Another way is that you learn from the defilement. When you understand something – that defilement is conditioning, or defilement is nobody, defilement is nature, defilement is Anatta, this is cause-and-effect process, there is nobody there – if some understanding arises, or when the defilement becomes just an object, any understanding arises, then the defilement disappears.