Generally, Quartz is the master healer above all crystals. It is the most powerful healing and energy amplifier. This crystal raises energy to the highest level possible and works on all levels of your being.
In addition to the generic attributes of Quartz, the Blue Quartz assists specifically in reaching out to others and alleviates fear. It aids in understanding your spiritual self and inspires hope by calming the mind.
In essence, if there is one universal crystal you need that focuses on communication and alleviating fears through instilling hope, it is the Blue Quartz.
How to cleanse
The Blue Quartz, like most crystals, should be cleansed periodically.
My best recommendation for cleansing your crystals is to do so with smoke. This could be from sage, Palo Santo wood or incense sticks. Allow the smoke to engulf your crystal and visualize its energy being renewed. After cleansing it, set your intention for your crystal by holding it in your hands and speaking your affirmation into it. This could either be specific or more general. Since Blue Quartz relates to communication and calming the mind, you can set intentions relating to these two aspects of your life.