There is a practice called mindfulness of the mind (cittanupassana). What it does is to make you more aware of what is going on in your mind by increasing the sensitivity of your mindfulness of the mind. You would typically focus anywhere inbetween the top of your head to around the level of the heart. Emotions and thoughts can be felt all over this region. It is possible to dvelve into the fears for example and feel what you are afraid of. Every emotion has a thought attached to it, telling us what the emotion is about. We often only watch the emotion from a distance or only skim it with our mindfulness- here you can sink right into it- then you can feel the irrational thought which is actually giving rise to that unnecessary emotion. Now if you can also keep challenging this thought with a rational one, each time it arises, you will find that it fades away. This is how you can little by litte wash away the defilements. Also it is said that the seven factors of enlightenment also help in weeding out the most subtle defilements (sabbasava sutta), so dont stop the samatha.