But doesn't cleansing the soul after breaking karma prevent what they call "karma purging"? I believed that if we don't clean the Karma thoroughly after breaking it, the karma that we broke can back fire. I read that in order to prevent this, it is necessary to cleanse after.
Can you also recommend a pranayama that I can use between spells and meditation? Which one do you usually use? What's your favorite?
I have noticed the chakras associated with the karma are dirtier than normal over the course of the day, not just necessarily right after. In regards to "back-firing", this should be thought as like stabilization or creation of new patterns. Sometimes this is stressful and there is resistance, but back fire can be a pretty harsh word, also giving the mental idea that it is something which can be entirely avoided.
In reality, you should think about the back fire as like a learning process, but the cleaning and more protected we are, the easier it will go. Maybe you do a Saturn Square, for example, and instead of losing your job, you only get yelled at. In both of these situations, you learn from your mistakes, but the first is much harder to recover from. An even better example would be like where you learn what you did wrong without anything obviously bad happening.
So yes, please clean more than normal to make everything go smoothly, but I would not assume that the cleaning has to specifically be done right after, otherwise bad things happen. This could be an overly restrictive conception about a process that is a gradual transformation of the patterns of the soul.
Regarding your words about "cleaning the karma": The karma is the process or pattern itself. The dirt is the outcome of that pattern, and/or energy which can negatively impact our existing patterns. There is a big overlap here, though. It is possible to break karma without cleaning, but this can be unstable and painful. Simultaneously, it is possible to clean the soul without breaking specific patterns of karma, but the negative karma will naturally release more easily from a higher purity of the soul.